My opponent blocks with gomer banded to my armor bearer, he has heze's ring up? Is he able to search my deck/discard pile for a philistine or not?
He may exchange to HIS locations, as it is read by his perspective by default (the player who controls the character). He cannot search your deck/discard.
However, if he does exchange, then Armor Bearer goes to YOUR location (so if to deck, to your deck, if discard, your discard) and then permanent control of the new Philly is actually exchanged as well...so that Philly goes to your territory after battle, if it survives.
It's a fun case