Wilma and Bert Stone: Judi Dench and Bill Nichy (they are Tom's parents)

Patricia Williams (Nee Stone): Emma Thompson (Tom's sister)

Quinn Stone (Tom and Claudia's sister): Lily James (she will be taking Quinn's place in season 7+, Quinn lived with her Aunt in England when she turned sixteen, she is know nineteen)

Reign Williams: Juno Temple (Cousin to Quinn, Claudia and Jack)

Kieran Melton: Taron Egerton (Reign's boyfriend)

Joseph Williams: Jeremy Irvine (Reign's older brother) 

(This is not final so if anyone has any different people they think should play these roles instead please let me know in the comments section! Thank you!)