Well, I'm a belter and I played Guenevere in high school. (And it *is* spelled Guenevere in the script, though I know in many Arthurian legends its spelled with an 'i'.)
Contrary to popular belief, some belters are versatile and can't get through an entire song without belting one note! 'Magine that.

I actually think Sutton would be interesting take on the role, acting wise.
I think Laura would be good, too, and probably the more likely choice of the two.
"You! You are the worst thing to happen to musical theatre since Andrew Lloyd Webber! And you, well, I just plain don't like you."
~Stewart Gilligan Griffin