Ambrose would be great as the Baker's Wife! I'd love to see that.
Murphy would be my top choice for the Witch, but she's not enough of a name to do the show if they are, in fact, looking for a "name." She'd be ideal in a full-blown revival though, even if she apparently is not doing revivals anymore (wonder if she has changed her mind after the poor critical reception of the last two original shows she has done).
Chenoweth might be good, she reminds me of Bernadette Peters sometimes with all the cuteness (though by this point in her career, Peters had shown more range and versatility than Chenoweth has but it's never too late). She'd definitely nail the comedic aspects of the role, and it's not as dark a role as Fran in PROMISES, PROMISES. She's certainly more of a name than Murphy, but still not big enough I imagine for what the Public is going for.
"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"