Yeah he was just being a wise-ass or something I dunno. Stronger wasn't listed as a crewmember in one of the databooks so he's not one.
Yep. While everything's possible and Stronger could be more than what he appears to be, so far there's nothing, not even the slightest foreshadowing or hint, that he's anything but Doc Q's horse. He may have a DF or some other ability, but he still is just Doc Q's companion.