I am currently a build of rogue/seeker/vigil with rogue boosting seeker.
My attack bonuses for unarmed are
+2 signature weapon mastery (vigilante bonus)
+2 Unarmed bonus from Ki strike 4/5 (it reads as a monk bonus)
I then cast divine favor. Divine favor shows +3 Attack bonus, however I only get a +1 bonus.
This seems to indicate that, it does not stack with bot overwrites the vigilante/rogue method for signature weapon, or the monk bonus which seems very incorrect.