James Risner Owner - D20 Hobbies |
Polymorph school says the GM is the “final arbiter” on what is it isn’t based on your form.
As a GM I’d say the class features you keep except Ex class features that I feel “modify” your base form. Like Wings (Ex).
Also keep in mind two polymorph or size changes don’t stack, so a lot of mutagens that are tagged as polymorph will not stack. Beastmorph at 6th is a polymorph (uses beast shape I). It’s probably intended at 1-5 but not stated.