SIZE Bonuses and stacking

[Seeker 26]

I'm DMing for a:

Ranger/Vivisectionist/Beastmorphing/Master Chymist

and a

Wildshaping Druid

and they are wanting to stack:

FEAT --Improved Natural Attack
FEAT --Powerful Wildshape
SPELL --Greater Magic Fang
SPELL --Enlarge Person

Do these stack for purposes of natural attack damage?

If not, do any of them stack?

(Also, is there a reference for this)

[DiscOH]

Powerful shape doesn't touch damage:

When in wild shape, treat your size as one category larger for the purpose of calculating CMB, CMD, carrying capacity, and any size-based special attacks you use or that are used against you (such as grab, swallow whole, and trample).

It lets you grab (etc) things one size larger.

The rest check out.

http://www.d20pfsrd.com/feats/general-feats/powerful-shape

[Mucronis]

Polymorph rules from the Paizo PRD.

"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. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell."

So assuming it's the druid wild shaping. wildshape and Enlarge person does not stack, improved natural attacks and greater magic fang works (might i suggest you look at the spell called Strong Jaw aswell, it would stack with the imp natural attack and GMF)