Write a v2.0 is longer and harder than I believed.
So, I will told you of the great lines of my reasoning in order you can help me.
The war
# In my thought, the spanish presence in the Netherlands is compromised as, the 'Spanish road' being cut, the army of Flanders becomes very reliant upon spanish fleet for his supplying, what will be very hard with the Dutch.
Spain will not be able to support very strong forces and the Spaniards would be in numeric inferiority with a ratio of 2 against 1 at least. Thus, after some attempts to bring the fights in France or Holland proper, and in spite of the tactic superiority of the tercios, the strategic advantage of the French and Dutch will, after some times, drive the Spaniards into a defensive strategy.
# In Holy Empire, with the Brandenburg then Denmark (for the reasons I've exposed in the TL) in the side of the Prtoestant Union, northern Germany will become a protestant stronghold. The fights would thus occur essentially in Palatinate, Saxony and Bohemia. But ponctual french offensives in Bavaria aren't excluded.
# In Italy, after the initial campaign of Lombardy, the front will be cristallized in the siege of Genoa.
With a naval presence far less threatened in Mediterranean sea, the Spaniards will be able to supply the besieged town, but not to retake Lombardy.
The opening of a new front in Italy will wait until the crisis of mantuan succession.
I imagine that the Pope, Tuscany and Parma will join the Spaniards. I think that Modena, hoping to retake Ferrara, could join the French.
But I'm more hesitant with Venice. The savoyard expansionism (pretentions over Mantua) could be felt as a threat. But a compromise could be Charles Gonzaga put on the ducal throne while recognizing himself as vassal of Lombardy. What's more, I thought to transpose the conspiracy of Bedmar in this TL.
# As the situation in Flanders would appear very bad to Spain, the opening of a second front would be necessary.
What's more, a 'Union de armas' could likely be launched to better share the effort of war. That would rise the tensions in Catalonia and in Portugal.
So, we would have one or two invasions of Languedoc, but the French could bring the war in Spain as soon a revolt breaks out, like the OTL catalan revolt of 1640.
Here, the war will surely take a great turn as Portugal will likely follow Catalonia and declare independance.
Portugal being tied with England by an alliance treaty, we would have England entering in the war.
The sequel would be an english expedition against Cadiz. For this work, Raleigh would be released. If the expedition fails or doesn't occur, english troops would be anyway landed in Portugal to help the secession.
The revolts of Catalonia and Portugal and the entry in war of England would lead to the fall of the Duke of Lerma.
# More generally, the entry in war of England would mean the end of the Spanish Netherlands. With both english and dutch navies in the fight, supply the Netherlands would be impossible. I doubt that the Spaniards would be able to hold a long time in the region.
The end of war should follow quickly. The spanish fortresses would surrender one after one, then Spain would have to sue for peace.
With Spain, leaving war, the other states (Holy Roman Empire, Papal states, Tuscany...) would be forced to make peace.
A war would last most around 6 or 7 years than of 30.
#A butterfly effect of TTL is the birth of a son to Christian II of Saxony and Hedwige of Denmark.
After the death of the former in 1611 as IOTL, there would be a regency with Hedwige and John George.
I think it would lead to a deeper involvement of Denmark in north Germany, especially as Hedwige would become pregnant while his brother enters in war.
# In the peace treaties, the independance of Portugal would of course assured, but I'm less sure about Catalonia.
I plan that the county of Burgundy and the duchy of Luxembourg would be retained by Spain, but the Netherlands would be shared between France and United Provinces: Artois, Cambresis, Hainaut to France, and Flanders and Brabant to the Dutch. For the French, the abandon of claims over Burgundy and Luxembourg isn't very important as the partition of spanish Netherlands eliminates a great threat over the northern frontiers of France.
In Italy, the annexation of Genoa, Milanese and Mantua (as a vassal) by Savoy, which becomes the Kingdom of Lombardy, are recognized. Modena receives Ferrara. Maybe Venice could have some gains in Polesine.
Spain receives Corsica, its only gain of the war.
At the time of the Peace treaties, the Holy Roman Emperor should be Matthias. About terms between the Catholics and Protestants, I have no particular ideas. Don't hesitate to make suggestions.
After war
France
# As Henri IV seems to have planned it, ITTL, Louis XIII will be married to Nicole of Lorraine in order to annex Lorraine as for Britanny before.
# Louis should become king around 1625/1626 (the date isn't yet decided). Richelieu will become chief minister as in OTL.
# Contrary to OTL, Louis will not have children, and the crown will pass upon his death to Gaston of Orleans, a more liberal mind I believe. Thus, with more and more concessions as the years pass, France will become by late XVIIth century or early XVIIIth century a parliamentary monarchy.
Italy
# The main consequence of the war is the creation of the Kingdom of Lombardy, surely the first step of an italian unification. The unification will be hard and will be realised by dynastical weddings, wars of sucessions...
Many coalitions risk to be created against Lombardy, Venice being not excluded to participate to some, to counter the nascent expansionism. The alliance with France would be essential.
Spain
# Because of the war, Philip IV would be married after the war, maybe as a part of the treaties, to Henriette Maria. The prince she will give to the spanish crown would be far better than Charles II.
# Without the cost of the Army of Flanders and of garrisons in Lombardy to support, the state of the spanish treasury would be better than in OTL, I think.
# The loss of the Netherlands would cause a reorientation of the spanish core of power more to south, in the western mediterranean sea.
A renewal of the spanish presence in Maghreb could be possible.
England
# A butterfly effect is the survival of prince Henri Frederick who will become Henri IX. Better relations between the Parliament and the King could thus prevent a civil war.
# Because of the war, the crown prince, Henri Frederick ITTL, would be married to Elisabeth of Bourbon instead of Henriette Maria.
Triple Union (Russia, Lithuania, Poland)
# As writed in the v1.0, the premature death of Sigismund III at Smolensk permits to enact the project of crowning the prince Wladislaw as Tsar.
The consequence is a better position for the Polish in Russia.
So, Smolensk falls earlier. However, the war will not be over.
There is still the threat of the Swedish, a threat especially important since Denmark, waging a war in north Germany, will not attack them before the peace treaties.
What's more, there would still be Dmitry Pozharsky.
ITTL, the Polish aren't thrown out of Moscow.
I imagine that Michael could refuse the crown (IOTL, he had hesitations to accept it), but there is also the possibility for Pozharsky to become Tsar.
Anyway, my objective is to make the Polish victorious.
Sweden could abandon Russia against concessions in Ingria, and maybe in Livonia, or because of an attack of Denmark after the end of the war in western Europe.
# The reign of Vladislav should be used to cement the union between the Polish and the Russians.
The polonization of elites excepted, we would have an expansionism as a mean to reach this goal. As example, Polish and russian settlers could colonize together Siberia.
Ottoman empire
# ITTL, the ottoman empire will be, more than Spain, the big looser.
I plan to have Abbas I of Persia allying with the Triple Union.
The Triple Union have interests in the matter as the fights between the Crimean Khanate, an ottoman vassal, and the Cossacks, under polish sovereignty, are source of tensions with the raids from both sides in their respective territories ; the polish magnates also have great interests in Moldavia.
What's more, these conditions would be very favourable to the project of Charles Gonzaga to create a greek state. For Lombardy, it would be move away a vassal to strenghten control over Mantua, and for Venice, a puppet state would be an assurance of safety for the venetian positions in eastern Mediterranean sea.
Against a such coalition, the Ottomans would have little chances to win.
The result would be Mesopotamia annexed by Persia, Crimea annexed by the Triple Union, a venetian puppet state in Greece and a polish puppet state in Rumania.
Persia
# A notable consequence of TTL is the survival of Mohammed Baqir Mirza who escapes to disgrace.
Indian ocean
# I think that Portugal could retain his possessions in Oman and East Africa in spite of losing Ormuz.
America
# In New France, Champlain manages to be appointed Governor General and after the War, he reinforces the french colonies.
# ITTL, the french colonies are not victim of english raids from Virginia because of the war in Europe as I imagine the English wanting to be as neutral as possible.
So, the french rule expands more to south, in Maine with the fondation of Castine.
# ITTL, an other butterfly effect is that the Mayflower goes more south than IOTL, to the mouth of Hudson river.
Sciences
# ITTL, Galileo Galilei is luckier as in his choice for the character who defends geocentrism, he is more careful and doesn't lose the support of Urban VIII.
A suggestion to replace Simplicio is welcome.
So, he continues his works in astronomy and mechanic.
There, I let you the choice of making or not of Galilei the discoverer of the universal gravitation laws and other OTL Newton's discoveries in mechanic.