Well, it's worth a shot. I have an old mission where I messed around with ship-create among other things, it would be a 5 minute job to make it an MP mission and test it. In fact, I'm gonna do that right now. Once I dig it up.
[Edit] They spawn well enough in MP, and seem to take orders too. I crashed shortly after though, but it seemed to be unrelated as it was just an assert during a weapon switch (and I wouldn't put much stock in that - Build was oldish and the mission referenced all kinds of crap that wasn't available as I didn't bother to enable any mods).