Okay interesting, so most likely the kid would be born at the latest around 1521, might this prevent Henry chasing after Anne? And thus prevent the whole split from Rome or delay it a little? And I guess, Catherine becoming pregnant around 1528, would be little to no chance?
Anne would most likely become his mistress or a confidant, if she manages to say no for long enough and earn his admiration. The only reason Henry became infatuated with marrying her was his sonless marriage to Catherine, a problem not had here. I can see him finding her an Earl to marry and keeping her at court to treat as a sexless mistress. And England will definitely say Catholic while Henry is around. With the one-two punch of that grand title and a son, he'll be feeling very fond of the old Bishop of Rome. Most likely he goes full Isabella I of Castile at some point and forces out all those with Protestant sympathies (possibly including his buddy Anne). And no, Catherine had definitely undergone menopause by 1524, so I doubt a 1528 child would occur.
Now onto these children. Mary was, as of her brother's birth, betrothed to the Dauphin. However, I can see this not going through if Catherine can help it. But it is the most attractive of the options, particularly after Charles V, Holy Roman Emperor marries Isabella of Portugal. Now for our Prince of Wales, there's a few options. There's Madeleine and Margaret de Valois, Maria of Spain, Dorothea and Christina of Denmark, Catherine de' Medici, Eleanor of Toledo, Maria of Portugal, Sophia Jagiellon, Margaret of Parma, Louise and Renee of Guise, Maria Manuela of Portugal and Elisabeth of Austria. Out of these, I can see either Margaret de Valois or Maria of Portugal making good brides. I would most likely endorse a match between Maria of Portugal, if just for varieties sake.
So:
Henry VIII of England (b.1491) m. Catherine of Aragon (b.1485) (a)
1a) Stillborn Daughter (c.1510)
2a) Henry Tudor, Duke of Cornwall (b.1511: d.1511)
3a) Henry Tudor, Duke of Cornwall (b.1513: d.1513)
4a) Henry Tudor, Duke of Cornwall (b.1515: d.1515)
5a) Mary Tudor (b.1516) m. Francis de Valois, Dauphin of France (b.1518: d.1536) (a)
6a) Stillborn Daughter (c.1518)
7a) Henry Tudor, Prince of Wales (b.1521) m. Maria of Portugal (b.1521) (a)