Raya, Flynn, and Maximus were Adam Green. Dumbo/Mickey were done by Tony DeRosa and Madam Mim was done by director (and animator) Trent Correy.

I believe that [Madam Medusa] was Hyun Lee!

Tony DeRosa did Scar!

Carpet/Mr. Toad/ladder - Michael Woodside
Ichabod - Trent Correy
Goofy/Fairies - Mark Henn
Jock/Trusty - Hyun Lee