Hi! The soloist on that album is Darlene Gillespie.
If you're a fan of the movie and don't have this album yet, I highly recommend picking it up: It's one of the most imaginatively arranged Disney albums ever. Until the release of the excellent restored soundtrack Randy produced, it was the only official version of the music available.
I've always loved this score. Now, with the availability of the Camarata/Gillespie album, the restored soundtrack, and the FANTASTIC mix of the Alice ride music on the 50th set, I am one happy fan.