Here's what I would do: Sell your compliant model before you move, as a Compliant model is less desirable and valuable in normal state. Once you move back into Free America, buy an M&P 15 with flash hider and collapsible stock and all the other goodies you want.

Yes, you could put just about any AR barrel on your rifle, or have your current barrel threaded, but why bother? As long as you can get a decent price for your current rifle, just buying a whole new gun will likely be cheaper and easier.