If you were in charge of casting a movie of this book, who would you cast as each character?

I think Jane Fonda as Mary Treat.

This is a tough question! It would be helpful if someone more knowledgeable than I am of film stars and roles over time would suggest several options for each character and let us choose? Anyone able to do that?

So far Gene Hackman grandfather, Louis CK -Iano, Holly Hunter -Willa, Emma Watson-Tig, Still thinking...

Ooo, what a fun question. Let's just re-purpose the Game of Thrones cast.

Iano - Nicolag Coster-Waldau (Jaime Lannister)
Willa - Michelle Fairley (Catelyn Stark)
Tig - Maisie Williams (Arya Stark)
Nick - Jonathan Pryce (High Sparrow)
Zeke - Richard Madden (Robb Stark)
Helene - Lena Headey (Cersai Lannister)

Thatcher - Kit Harington (Jon Snow)
Mary Treat - Rose Leslie (Ygritte)
Rose - Natalie Dormer (Margaery Tyrell)
Polly - Sophie Turner (Sansa Stark)
Rose's Mother - Diana Rigg (Olenna Tyrell)
Captain Landis - Sean Bean (Eddard Stark)
Mr. Carruth - Jerome Flynn (Bronn)

Willa/ Meryl Streep
Iano/ George Clooney
Nick/ Jack Nicholson
Mary Treat/ Renée Zellweger