Does the damage from Crushing Grab and Brutal Bully stack?
This is sort of a repost of this thread.
As I said in that thread, I see no reason why they wouldn't. Duplicate Effects only covers effects with the same name that provide the same bonus. The damage done by either feat also isn't a "bonus" so there is no reason for them to not stack from that perspective.
So as worded, there is no reason why they wouldn't both apply. I could see a GM ruling that they don't, but with the feat investment required to get both effects going (even with Free Archetype) I definitely don't see this as a pure exploit.