Thank you for this great guide !
A comprehensive transmuter guide was sorely missing.
A few suggestions :
Alternatively to a wizard, an arcanist with the archetype School savant (transmutation: shapechange) works really well as a master transmogrifist: with access to exploits letting him cast and switch forms while polymorphed it rocks.
For Magical Beast Shape: You might want to take a look at lesser bandersnatch,
Thrasfyr and Kokogiak. All nice huge combat options.