Reatraining a feat normally takes 5 days of downtime. Perhaps an alternative in this campaign might be to retain it *during* level 4 – however long we are at that level for. Like – he’s working on an inquisitor judgment surgey thing because he *already* had heavy armour proficiency like a fighter – he was already halfway there. Arguably, that’s what’s happening now during level 3 … meh. Let’s see what Brett is cool with.
Oh BTW: I was quite wrong about only getting the 1½ str bonus on a natural primary weapon when not making a full-round attack. You get it unless you are making attacks with a different weapon. So, if a creature has a bite-claw-claw routine, the bite does not get the 1½. But that’s not the case with Brus.
Incidentally, I just realised. The lucerne hammer is a reach weapon. The toothy bite is not. So Brus threatens all squares up to 10′ – fun times for flankers and sneak attackers.