Greetings, all!
I'm aware that Enrage normally prevents the affected character from using magic, and many or all Polymorph skills are or should be magical; however, if I've already activated a Polymorph skill (wings in this case, but it may also apply to Spider Legs, Medusa Head, etc.), then I feel I should be able to use these. The magic was in the transformation, not the use of the ability thereafter.
That was the first time that using Enrage made me as a player mad: I did it before flying into position.