I would get a barrel for 5.56 personally. I have read its not recommended to shoot 5.56 out of a .223 barrel but you can shoot a .223 out of a 5.56. Im not sure on buffer weights. And if you shoot factory ammo or surplus I don't think you will have a problem. I bought a stag arms AR and it eats...
Sounds like you are having fun. I have lost countless small parts that went flying in the living room only to find them months later in some spot where it should not fit or managed to get in. What brand and caliber upper are you looking at getting?
Here is the stock I have on my 10/22
Amazon.com: Archangel 10 / 22 Deluxe Target Stock, BLACK: Sports & Outdoors
I like it but thinking of changing it out for something with a adjustable butt stock. Your 10/22 looks nice have you had a chance to shoot it yet?
I use a plain old 870 with a 28" barrel and factory choke. I do OK at busting clays with friends. The mossberg and 870 are extremely versatile guns and can be changed when you out grow them.