I was wondering who Isabella and Ferdinand's other children would marry in this world... I suspect it would look something like this:
Isabella of Castile (1451-1504) m.1469 Ferdinand of Aragon (1452-1516)
- Isabella (1470-1498) m.1490 Afonso, Prince of Portugal (1475-1491) m.1497 Manuel I of Portugal
- Miscarried son (1475)
- Juan (1478-1497) m. Margaret of Burgundy (b.1480) [1]
- Juana (b.1479) m. 1494 Henry VII of England [2]
- Maria (b.1482) m.1500 Manuel I of Portugal [3]
- Catalina (b.1485) m. 1501 Phillibert II of Savoy [4]
[1] I'm not sure the Catholic Monarchs would still want the Austrian match, if it's not part of a double match, but I couldn't think of anyone else for Juan. Happy to change it if anyone has any better ideas.
[2] The way I see this working is: The Ambassadors are there to arrange Catherine's match to Arthur as OTL, but then Elizabeth dies in childbirth and the English court is plunged into mourning for the better part of a year, stalling negotiations. When they are reopened in 1490/91, Henry needs a new wife with Lancastrian heritage, and the eleven-year-old Juana is thought to be suitable, so Henry and Juana's names are exchanged for Arthur and Katherine's on the marriage contract....
[3] Yes, Portugal goes as OTL, because I'm too lazy to consider butterflies here too...
[4] I was going to marry her to Charles III, but I wasn't sure her parents would be willing to wait until 1504 for her marriage and Phillibert's first wife died in 1499, so he slotted in perfectly ahead of his younger half-brother.