Yamanami is still technically the fukuchou, so he's going to try to act like one. Thanks to his mallynap experience, he's already been forced to confront all of his various phobias, but hideous failure i.e. freezing at crucial moments might happen and if blood gets everywhere, well...

HE WILL TRY HIS BEST EITHER WAY. He's mostly defensive, so he won't be very effective until someone gets hurt, and then he'll lose it and be his "old self" for a bit.

And I'm guessing Heisuke will be sticking to him like glue.