Do racial penalties and bonuses apply if I change my form? If I get +2X/-2Y because I am race A, would this change if I altered form into race B? Would racial bonuses stack or be replaced by the +/- str/dex/ac/nac etc?
Don't worry about your original race. Dwarven wizards turn into particularly tough dragons and elven wizards turn into particularly graceful ones. Polymorphs are now a template you just add to your character.
From the description of the polymorph school (where most of the info is)
Your ability scores are not modified by this change unless noted by the spell.
If I use beastshape, form of the dragon, and the like, can I cast enlarge person on myself in addition?
no.
In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.
Specifically I am a gnome (small) and become medium (form of the dragon), could I cast enlarge on myself to become large? I'm guessing I can't because my size was already changed, but wanted to double check. What if I were medium and cast beastshape/FotD on myself, could I cast enlarge to boot since my base size didn't change?
You can be a bear or a dragon. Not both.
You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell.
For Form of the Dragon, does anyone know if the bite and tail use the 1.5 str modifier like many dragons?
The description I found didn't specify what strength modifier to use for what so I'm assuming
Bite - 1.5 str
Claw - 1 str
Wing - 0.5 str
Tail - 1.5 str
You gain all of the natural attacks of the base creature, including proficiency with those attacks
I would say yes.
Thanks for the answer and references. Being a new player and trying to look all this stuff through online sources definitely leaves me confused.
No problem. We were all there once. Some remember and try to pay it forward. ANd have no life :)