Alicia von Rittberg and Jessica Raine are 11 years apart in age. Princess Elizabeth and Catherine Parr were 21 years apart in age. Elizabeth was 14 when her father died while Catherine Parr was 35.
Catharine Parr died (1548) of puerperal fever, at the time an illness that usually took some days to die from. Catherine died 7 days after giving birth. Thomas would have know she was sick and dying, rather than being a complete surprise. In 1537 his sister Jane Seymour died of the same illness, 12 days after giving birth.
Leo Bill who plays Henry Grey in this was previously in another Starz show dealing with the Tudors. He played Margaret Beaufort's servant Sir Reginald Bray in The White Queen.
Jessica Raine portrayed Lady Rochford , Anne Boelyns sister in law in Wolf Hall
Despite playing father and son, Jamie Parker (John Dudley) and Jamie Blackley (Robert Dudley) are only 12 years apart in age.