I'm seconding this, because it includes almost everything you could ever need to know about MoMF.

Also, iirc, Assume Supernatural Ability is like Divine Metamagic or Weapon Focus: you have to choose what supernatural ability it applies to (so you could choose "Breath Weapon" and get the supernatural breath weapons of your forms, or "Eye Ray" and get one wildly specific ability when you become a Beholder). I don't believe (could be wrong; haven't played an MoMF in a while) that ASA gives you all supernatural abilities of anything you wildshape into.