JonasResende said:
Also, Nicolas Henri doesn't exist. He was entered into most genealogies as N. de Bourbon (implying prince sans nom/nameless prince). The Henri part I imagine was a deathbed baptism (as with one of Louis XV's daughters). IDK where the Nicolas came from.
I think Nicolas came from the confusion that N. was an initial for his first name instead of showing the child hadn't been named. Not helping is that I think Henri IV has a Nicolas among his ancestors (practically sure it's not a Bourbon but names weren't necessarilly taken only from patrilineal ancestors only).
JonasResende said:
That said, Gaston running the country sees Marie de Medici stay in power a lot longer, though Cardinals Richelieu and Mazarin might have a harder time of things.
Not necessarilly. Richelieu started his political career with Marie de Medici technically: he served as minister of Foreign Affairs for Concini from 1616 onwards. After Concini's death, Richelieu was chased out of court because he had worked for Concini. After Marie took the had of a rebellion against her son in 1619-1620, Richelieu was one of the leading negotiator of the peace between the Queen Mother and the King. Louis XIII was also very hostile to Richelieu at first because of he saw him as one of his mother's men: which is why he didn't agree to ask the Pope to make Richelieu a Cardinal before 1622 and didn't allow Richelieu to enter the royal council before 1624. Richelieu started to swicth patrons and side with Louis XIII only afterwards, because he had understood that the King was the one truly calling the shots in France.
If there is no Louis XIII and Gaston becomes King of France (as Jean III like you suggested), then Richelieu would probably stay as a client of Marie de Medici and continue his political career in her service. It's possible he would follow similar policies to OTL, in particular with the nobility (reinforcing Royal Power is probably something any King would want) and the Protestants (They were considered too powerful and Marie was certainly not their biggest fan). He probably wouldn't be able to take the foreign policies he had OTL though, unless a rift happens between France and the Hapsburgs or Gaston as King understands that if France is to become the primary power on the continent, Spain and Austria have to go down.
As for Mazarin... Well, considering it's Richelieu who made him who he became, Mazarin's career in France is dependent on his meeting with Richelieu. Otherwise, I imagine Mazarin would do his political career in his native Italy.