I'd build up a pistol with a brace of your choice. You already have a couple of SBR lowers so obviously you can run the .22 upper on either of those if you want just as easy as swapping whatever uppers your using on those sbr lowers over onto a new pistol lower. Another option is to use a cheapo brace like a KAK blade for now and submit your form1 then slap whatever stock you want on there when it comes back approved. Form1s fortunately are not taking anywhere near as long as form4s are at the moment.
I don't see the point though unless you really want to add another stamp to your collection. Only you can ultimately decide if the wait and additional money is worth it or not.
22AR with Dead Air Mask, Franklin Armory BFS3, Bore Buddy accessory upgrades.
Brace works fine for me
Are we planning to suppress it? A barrel shorter than 5 inches will keep most bulk pack subsonic which is nice to just use whatever you have on hand. I'm using a Velocity 4 in bbl. Most folks use and will recommend the CMMG 4.5 in bbl. Right to Bear out of FL is a good source of AR22 parts. Most of their house branded parts are OEM CMMG stuff at a discount. Best of luck with your project.
I highly recommend some of the borebuddy upgrades. Check out the bolt bounce thread.
https://www.ar15.com/forums/AR-15/Super-slow-motion-22lr-AR-bolt-bounce-eliminated/15-752521/