There’s 5 squad types – Reivers (scouts in power armour), Intercessors (Tacticals), Hellblasters (all carry 15cm range plasma guns, no bolters) and Agressors (cross between a Terminator and a Devestator). Primaris have the full usual range of SM characters too. I don't think they'd use any of the existing SM vehicles but I'm not certain.
They also have a large transport aircraft equivalent to Thunderhawk called an Overlord (though it looks quite different, more like a larger version of the
Deathwatch Corvus Blackstar apparently). I expect there'll be a model from either GW or FW at some point. That plus the Dreadnought and floating transport / battle tank along with titans and air gives them enough to make a slightly limited but usable list IMO and the range will surely expand in time. Given it's range of weapon options then likke the Predator the Repulsor tank could probably have two profiles, one an AT version with the las weapons and the other an AP version with the gatling gun and heavy bolters.
I'll wait and see if anyone makes models for the Primaris personally, I expect it's only a matter of time.
Possibly Primaris disucssion should take place in a dedicated thread though rather than sidetracking here.