Let's say that Mary I and Philip II has a son. Let's name him Henry, born in 1555. And that results in Don Carlos marrying Elisabeth of Valois. Don Carlos would have a son born in 1563. Let's call him Philip.
Let's assume that future Henry IX and Philip III would survive and have issue.
What's the long term repercussions of a Catholic Habsburg England not in union with Spain? How does that affect the Dutch revolt, and the character of North America?