"Might Action Skill Rolls" are not the same as damage rolls. Action Rolls are 2d10+(attribute)+(skill bonus); damage rolls could be any combination specific by the action undertaken.
You can spend Fate on Action Rolls but not damage rolls.
+2 damage and +2 Might rolls (note; not Might Action Skill Rolls) may stack if different sources.
Primal Self wrote:
When in this form you gain a +2 bonus to all Vitality, Might, and Quickness rolls. Also, you gain a +2 bonus to all Perception Action Skill Rolls and a Speed: 4 natural melee attack that deals d8 (Mi) damage.
Source: Talent; Type: Static; applied to all (Vi)(Mi)(Qu) rolls of any sort.
Weapon Mastery IV wrote:
Tier IV: You deal an additional +2 bonus damage when
attacking with your mastered weapon.
Source: Talent; Type: Static; applied to damage rolls.
Bestial Form wrote:
Effect: For the remainder of the Scene you gain d6 (Mi) natural attacks (claws and bite), a Pace of 50’, Natural AR of 6, and increase all your physical attributes to d12, while decreasing your discipline defense by 1 and all of your mental attributes to d6.
Your also gain 2 of the following traits chosen at the time of casting: Crush, Monstrous Charge, Owl Eyed, Ravenous, Stealthy (Tier 1), or Wolf Pack Tactics (pg. 212).
While under the effects of this spell, all of your equipment melds into your new form (becoming unusable for the duration of this ability).
Special (val’Dellenov): If you cast this spell while under the effects of The Primal Self Bloodline Talent, you gain a +2 bonus to damage and all Might and Quickness Action Skill Rolls.
Source: Spell; Bonus: Static -- Note that the Special changes the Source of the bonus!
** d6 (d12)+2 unarmed damage is pretty good; d8 (d12)+2 with Iron Fists or d8 (d12)+4 with Unarmed Weapon Mastery IV (Talent/Static). Add +1 from Wolf Pack Tactics (Trait/Static).
For the sake of completeness:
Item Quality wrote:
Weapons: Weapons of Fine quality deal an additional point of damage. Exceptional weapons also have excellent balance, lowering the weapon’s base Speed by 1 (to a
minimum of 3) in addition to dealing 1 extra point of damage with every hit.
Source: Item; Type: Static; applied to damage rolls.
Two Talent sources, one Spell (+bonus Trait) and one Item. Apply stacking as appropriate