Orihime and Chad unlocked their inborn powers thanks to Ichigo's spirit energy when he was in shinigami mode. Ichigo did not give them superpowers, they already had them, his strong spiritual presence was just the push they needed to unlock them. Otherwise Tatsuki, Karin, Mizuiro etc, all his other friends who came in contact with him, on a regular basis would have had some kind of powers too, which they don't. Makes sense for now I guess, but that begs the question, what are they actually if not shinigamis?