My question is, who would be his heir? Tupac had three sons.
Another question, how would the next heir treat the Inca culture?
I imagine active callbacks to the Inca Empire in ceremony/habits/governance/fashion/etc. would go in and out of vogue, depending on the Emperors, the bourgeois, and the academic classes. As for individuals of Quechua or native descent and their social standing, it's inevitably going to be messy. The Empire(at least, in my theoretical best-case scenario wank) has turned TAII's personal motivators into its founding ideology, to the point that IMO it'll be to the Inca what 'Liberty and Justice' and their deathly fear of taxes was to America. The Inca Empire would be running on racial egalitarianism, economic justice for the lower classes, and (to the upper echelons) a strange mix between economic paternalism and social responsibility with a healthy dose of enlightened absolutism from which both the paternalism and social responsibility derive from. All of factions within the Empire are unified loosely by this ideology, or at least parts of it.
Now, Tupac Amaru's inner circle is a pretty healthy mix of all the major racial groups(except Afro-Latinos); Criollos, Mestizos, and Indio. The bulk of the army is Indio due to the nature of the revolt being primarily built on racial injustices thanks to the the Encomienda system though all are present. Spanish is unquestionably the language of communication for the army post-war due to the Indio elements being more diverse than simply Quechua-Aymara and the endgame campaigns taking place in New Grandad, though Quechua is likely seeing wide usage and for the first time in a long time, has a prestige language element to it in a similar vein to Latin, Persian, or Sanskrit. In addition, Quechua and Aymara were likely the primary language of the army up until around the fall of Lima, where Mestizo and Criollo soldiers became larger factors in the war. Spanish is likely seeing a very large influx of Quechua words right now due to the military, but Quechua is lowkey approaching some form of standardization as well, something which IOTL greatly hampered its usage. I think it's very likely that you'll see a large amount of interest in Quechua in all elements of Inca society as a result. I'd expect the following:
1) Quechua will shortly be standardized either colloquially or formally as it'll be incredibly useful in the revitalization of the Andes' economy and in the army
2) Indios who only speak Spanish, no matter their background, will be drawn to Quechua due to its increased prestige and the increasing social standing of the Quechua. As will all classes due to its 'Latin'-like status in the realm, especially artists and intellectuals
3) Aymara as a language is going to be succeeded slowly by standardized Quechua; consider the passage below:
Quechua shares a large amount of vocabulary, and some striking structural parallels, with
Aymara, and the two families have sometimes been grouped together as a "
Quechumaran family". That hypothesis is generally rejected by specialists, however. The parallels are better explained by mutual influence and borrowing through intensive and long-term contact. Many Quechua–Aymara cognates are close, often closer than intra-Quechua cognates, and there is little relationship in the
affixal system.
It's going to survive, naturally, but it's essentially going to serve as the odd country tongue that's going to follow standard Quechua(which is going to draw from the Quechua-Aymara shared vocabulary pool heavily anyways considering how dominant it is within the Quechua language family anyways) along every step of the way. Essentially, two languages sharing one vocabulary to the point of easy comprehension off vocabulary alone but never quite intelligible. It's going to have a hell of a lot more impact on standard Quechua than northern Quechua ever will, anyways. 'Army Aymara' will essentially be what modern-day Aymara will descend from in the long term.
4) Spanish will remain the language of trade and government, though Quechua will likely be made co-official by TAII due to the origins of the modern Inca state in the Altiplano's Indio armies.
What does this all mean? The Criollos are likely the most lukewarm supporters of racial egalitarianism; IOTL the driving goal was to establish the Criollos as the leaders of society, not to topple the entire social structure. But in this world, they're ruled by an Indio, the army is largely composed of Indios, and so on. They've essentially got to play ball because they placed their bets that equality will still see them prosper over the previous situation(and they're right, to an extent). Criollos still make up the majority of the elite in the most important cities and towns of the Empire as most saw the writing on the wall and properly changed their allegiances. The largest of their excess has been reigned in and they've undeniably made concessions to TAII, his Indio armies, and social pressure from the true believers and sympathizers of his ideology. But they're still largely sitting pretty at the top; most of the new upper echelons of Inca society consists of war heroes and generals, the family and allies of the Sapa Inca, etc. The Criollos still own large tracts of land though production has largely shifted away from cash crops; revitalization of the Andes economy and ensuring the prosperity of the common man is high on the Sapa Inca's to-do list, and this means ensuring that there's yields enough for the people to make merry and have children. Can't do that when you're growing sugar, especially when your previous buyer is no longer buying. As a result, the majority of South America is experiencing a population boom due to the decreased demand for plantation crops and increased demand for food(especially due to the campaigns of the revolution). Through equal parts pragmatism and laissez faire economic pressure, the Criollo elite are largely following through on the economic paternalism and social responsibility aspects of Inca ideology, and paying some lip service to racial egalitarianism, though economic justice is very low on their list, they still want the same prosperity and control they previously had with a few pragmatic exceptions. Meanwhile the average Criollo is in an interesting position; their social standing has risen, but alongside them they're rubbing shoulders with Mestizo and Indio commoners with whom many marched alongside with in war. They've picked up a few Quechua loanwords, they're in somewhat high demand due to generally being better educated than their peers and the need to organize a functioning government, and they're strong proponents of economic justice. The Criollo elite and the Criollo common man are actually on largely different footings; whereas one fought, the other conceded with of course, obvious exception existing in both camps. While the Criollo elite are influential with soft power, their hard power is largely non-existent, as they know they could soon walk on eggshells.
Mestizos of all social standings are roughly where the Criollo common man; trying to juggle their rise in standing with the need to be above someone(the Indio) who's now on their standing. Mestizos were enthusiastic supporters of TAII's message of economic justice and the extent that they supported racial egalitarianism usually depended on their exact place in the previous Encomienda system; obviously, the ones with more or recent Indio family were naturally the more enthusiastic, the ones whose family were largely Criollo or other Mestizos less so. Mestizos with fluency in Quechua quickly rose in positions of governance and to a lesser extent, trade as the need to form a government and administration for the diverse Inca state, and as such, Quechua fluency went from an oddity to a coveted skill to rise in government positions and to fit into the small renaissance the Quechua's legacy was experiencing in Inca society. Views on TAII are near universally positive, though the idea of Sapa Inca is met with some degree of skepticism, instead largely viewing him as the monarch of the realm.
Indios are the social class experiencing the wildest shakeup. Indios are the core of the army. Indios are a plurality of the Spa Inca's inner circle. Indios are the people that incited, led, and rule a land that stretches to just about the entirety of the old Inca Empire, in some areas far further, that dominates South America as the colossus of the continent. It was, in a phrase, a brave new world. Racism didn't disappear, obviously. Indios were still near universally viewed as uneducated, even by other Indios sitting in higher social stratas, and the vast majority in this period largely remained as peasants, though even they would experience a notable improvement in their place in society through the actions of the Sapa Inca. Social mobility for Indios was largely tied to one institution; the state. Namely, the army, and for the more educated, the government. Army men were war heroes and they reaped the rewards of their service; many picked up Spanish over the course of the wars of independence, many formed ties with people of all places in society thanks to the wars, many married women far from their original homes, and as a result many an ambitious soldier was able to attain a position as a community leader of newly established
Ayllus, translators, and in some truly exceptional cases, granted the title of newly formed(or in some cases, reformed)
Kurakas or government administrators. These men would be at the forefront of the Sapa Inca's campaign to abolish the Encomienda system, where the plantations and mines of old were either reorganized or abolished into Ayllus in the name of protecting the common laborer. The Indio populace of the Andes would quickly balloon thanks to the abolishment of the Encomienda system, the end of the wars of independence which saw many of the old plantations shifting from cash crops to food, and the establishment of new Ayllus by those who were displaced due to the war, though these tended to feature families of all races due to the Sapa Inca's (now self-propagating) ideology of racial reconciliation. This is the origin of 'Nuevos Indios', a modern term used to describe non-Indios originating from an Ayllu. Anyways as a result of the revolution, Indos have seen a notable increase in their quality of life thanks to all of the above-mentioned factors though the social mobility of the average peasant remains low barring joining the army, which is seen as prestigious and became the primary means that Quechua's standardization would spread to average Indio peasant, as well as the slow spread of literacy from the army to the peasant. Many returning army men in the coming decades would act as teachers for their communities, teaching Spanish, basic reading and writing, and mathematics once the army's role in social works was expanded and the expansion of literacy fell under its umbrella.
Why is the army focusing on social works? Well, Andean romanticism, the need for many public works, and the relative stability and weak neighbors of the realm in the long term means that the army will functioning in the short term as the revived Mit'a system and long term, will likely be the means through which the Mit'a system is revitalized for good in a form that's palatable to the European mindset of many in the realm. I doubt that the Inca can fully resurrect the Mit'a system in the face of Britain and the incoming revolution/dominance of capitalism, at least not in the short term. Long term? The Mit'a may just be the Andean solution to the social ills that follow capitalism. Though alternatively, the Mit'a may be a compromise means to reform the Encomienda system. A return to humane labor for a set period in peasant communities to work mines and plantations, while the army performs the public works element of the Mit'a such as road building.
-My two cents on race relations for the average non-descript person. The Sapa Inca and the government deserve their own focus with respect to how it works, the reforms made, key players, and policy. Ditto for the army, which I can't really avoid talking about with respect to the experience of the average Indio