I find both Hemsworths to be incredibly wooden on screen, which would work for the parts. I doubt Chris Hemsworth wants to do both this and the SNOW WHITE film though.
Kristen Wiig would be sublime as the Baker's Wife and she has been suggested by many from the time the movie was announced. She was supposedly one of five or six actresses being considered for Marshall's remake of THE THIN MAN, which apparently was shelved in favor of INTO THE WOODS, so I'm sure she is definitely a name that is actually in their sight. I'd much rather see her over more typical choices like Amy Adams or Sandra Bullock.
Jessica Chastain has gone on the record last year and this year (while promoting her different Oscar nods) that she'd love to do a movie musical. I wonder to what extent Marshall et al are considering her for the Baker's Wife.
And though many hated her singing in NINE (and I wonder if she liked the experience of working on it at all), I think Nicole Kidman could surprise everyone and turn out to be an incredible Witch. She lacks some of the earthiness that someone like Bernadette Peters brought to the role, but she'd find humor in all the unexpected parts. Her friend Naomi Watts would also be an interesting choice, if less likely as I doubt she sings.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"