Marshal / Factotum Build Question

[Sugashane]

I want to know if these stack as they seem to be untyped bonuses.

Marshall's Aura of Motivate INT- Add CHA to all INT checks and skill-based checks

Factotum's Brain Over Brawn- Add INT bonus to all STR and DEX based checks and skill based on either. This includes AC and Initiative (as it is DEX based)

So say it is a +4 modifier in both INT and CHA. Now this character would get (in addition to actual ability mod that is used for it):
+8 to attacks and damage (4 from INT and 4 from CHA)
+8 to AC (same)
+8 to initiative ((same)+12 with improve initiative)
+8 to all DEX and STR checks (same)

I may have missed a few things but does this look legit?

[A_S]

No...getting your int bonus to a check via a class feature (Factotum's Brains over Brawn) does not make that check an int check or an int-based skill check, so Motivate Intelligence would still not apply to it.

However, the issue isn't stacking, it's what counts for Marshal's auras to apply to. If you instead used Motivate Dexterity, the bonus would stack with that from Brains over Brawn for dex checks (so, you would get your dex bonus, your int bonus, and your cha bonus on initiative rolls).

*edit* Also, Brains over Brawn doesn't apply to AC, since although AC is dex-based, it's not a check (i.e., you don't roll a die for it).

Attacks and damage also don't benefit from either Brains over Brawn or Marshal auras. An ability check or an ability-based skill check doesn't just mean "any roll you add a given ability to." It's a specific term used in-game for certain rolls. You can read more about this here (http://www.d20srd.org/srd/skills/usingSkills.htm), but basically, unless it's called an ability check, it's probably not an ability check.