My dd was in Suessical Jr. and loved it. The interesting part about this musical is that the majority of the script is sung. Some of the leads have lines and a few others do too, but for the most part the whole story is told through singing. My dd played one of the birdgirls(there are 3 of them), which was a fun part. The birdgirls are in alot of scenes and have several trio singing parts as well as each birdgirl having their own one line singing solo in a couple of places.
Fun music (although you'll be singing it in your sleep !!), fun costuming, fun storyline, and perfectly enjoyable for all ages!
My dd was 12 when she did it and the leads were more like 15/16. There were kids as young as 10 in the cast as well, but again it was the Jr version. I've never seen the regular version, so I'm not sure which roles would be for children. Maybe all the "WHOS" in WhoVille.
Anyway, encourage your daughter to audition... she will enjoy being part of the show! Best of luck!
PS-If interested I can email you some pics or try to figure out how to post some on here...