The JE Machine Tech AR-15 Mil-Spec 6-Position Buffer Tube & CQB 4-Position Micro Stock Combo will fit and function as intended. As long as the kit is properly installed, you should experience very little play in the buttstock.
Yes, this system will work for your dedicated .22.
JE Machine Tech states the stock for this kit is made from polymer.
I bit the bullet and ordered it so I will answer my own question for those who follow and want an answer.
It comes with everything in the photo - stock, tube, buffer, spring, castle nut and end plate.
It comes with everything in the photo - stock, tube, buffer, spring, castle nut and end plate.