Brazil might only consist of everything east of the original Tordesillas Line.
I don't think so, the Bandeirantes gave around 0.00 shits about Tordesilhas, there's a documented situation where the Bandeirantes sacked an Incan outpost and went back to Brazil, getting ambushed by Guaicurus on the way back near Assunção.
Tordesilhas was a giant straight line drawn with absolutely zero knowledge about local geographic conditions.
Its generally believed the Portuguese had it pushed further West because they
knew there was land there. Its pretty much accepted historiography nowadays that the Portuguese likely already knew about the American Continent before Colombus. So they knew there was land, and that was about it.
There's no way Tordesilhas is lasting more than it is convenient. Straight line borders are a 19th century thing, and never found great purchase with the Portuguese and Spanish. They were all about using natural landmarks like mountains, hills and rivers to create distinguishable, defensive borders.
At the very least, I think the Portuguese will take over the Amazon as they did, because that position's geographic area just makes it easier for Portugal to own than for Spain - the logistics don't work for Spain at all, because the Portuguese own the delta so they can send whatever they want up the river.
While its not like the Amazon river, I believe similarly goes for other rivers like the São Francisco.
Brazil might less west than in our reality, but Tordesilhas simply doesn't work as a border at all. Even if by some miracle, Portugal keeps to that side, eventually sooner or later the other side is going to get demographically swamped by luso-brazilian colonists, just like what happened to the American Southwest. There just ins't much chance of the Spanish really colonizing that land, too inland and they got better places to go. Somewhere like Mato Grosso for example, its a bunch of inland swamp.
people often forget it because half of Brazil’s popualtion is mixed but the Portuguese descended population of Brazil actually exceeds the British descended population of the USA,
Very true. All the whole "Brazil is super-diverse" is actually overestimated. If you get a map showing primary european ancestry, the US has significant portions of British popullations and entire areas of other ancestries, like Italian and German. Meanwhile, the Brazilian Map is pretty much portuguese flags
everywhere, with the odd german, italian, french or spanish flag. Even that, from reactions I saw in facebook, these might be low-balling the sheer amount of portuguese.
I suspect more than half the population is mixed, actually. There's a lot of white people here, but unlike in the US, having some non-white ancestry doesn't make you instantly into a black or brown person. I suspect a lot of "browns" are actually very tanned whites while a lot of "whites" are actually light brown. A lot of white people have non-white ancestors.
A good example is my mother's immediate family: My maternal grandmother was half-italian and my maternal grandpa was a Cafuzo. Almost all my maternal uncles and aunts are luso-italian whites, but almost all have curly hair and white skin, with the exception of one uncle who is Cafuzo and looks like gramps' clone. However, I inherited more tanned skin, some african features and frizzy super curly hair from gramps, while my brother is pretty white. People generally consider me as white (white with some extras), and many of my documents have me as white.
The way race works here is very different. One-Drop rule doesn't exist here.
Deep down, Brazilians are Portuguese served with chocolate and some extras.
So the oldest European settlers will probably be mixed race, with significant number of Portuguese arriving only later?
Could that mean that the oldest settler families will be mixed race, while newcomers being white?
Yes, that's kinda how it happened in Brazil. But the newcomers will eventually mix and blend with the black popullation.
Thing is, the oldest richest families will "whiten" with time as more wealthy portuguese and other european people appear with time and society goes from frontier to more civilization. Then again, it might not happen as much if the entire colony is blacker in general. Its funny, if you take a DNA sample from someone from the oldest families of Brazil, you will see boatloads of ancient indigenous ancestry and sometimes even recent black ancestry, from people who look perfectly white.
If a class of wealthy indian merchants pop up, they might end up mixing with the portuguese elites.