He doesn't have a tadpole so it's unlikely. Tadpoles seem to be the glue keeping companions together, and overriding personal motivation when playing as origin.
Nonorigin companions would be great.
Yes, that's a bit the whole point, albeit implicitly. Larian has said that they're only planning 8 OC (Origin Characters), I don't think they'll make more. And I wouldn't want them to make any more anyway. I feel its a huge resource-sink and that there should have been at most 3-4 OC to begin with.
But what many people are requesting, when asking for Halsin, Alfira, Minthara, etc to be companions, implies that we could have non-tadpoled companions in the party. I'm not in everyone's mind, but I'd assume that most people who ever requested X or Y to be a companion understood that they would be non-tadpoled, non-OC companions.
I don't see how this would be problematic in any way in a coop game. Of course, in a 4-player coop game, there would be no space in the party for non-PC members. But that would also be true of at least 4 of the OC.