I built a 22 Creedmoor a couple years ago using an ARC Nucleus action along with their Bar-loc setup instead of a traditional barrel nut. You can swap out barrels easier & faster than a barrel nut. 22 CM barrels don't last very long!
I'm building a new 223 with another Nucleus action Gen 2, but will have a shouldered Rock Creek barrel on it. The only reason I'm going with a shouldered pre-fit on this rifle is that the barrel life on a 223 Remington is longer than I have left to live.
Your parts list looks like good choices to me!