get the 135mm Outlaws. the rear wheel can be switched between QR and 12x135 thru axle.
if your frame is QR...obviously you cant use thru axle. outlaws are interchangeable (the 135mm version only)
as for going tubeless stans will work fine. you can also try "ghetto tubeless" if you wanted to(do a search if you dont know what that is. most people will recommend to use Maxxis non-UST tires when going tubeless. again, do another search, there's alot on that topic.