A little excited?

Go easy on the parts, no special parts are needed, just 2-3 pieces for the lower. You have lots of time to wait for the deals to come up. They are just AR15 parts.
You certainly don;t need a $100 buffer.
This thread went up 16 months ago, Questar said probably 5 months to get them.
The wait is going to kill you.
The only thing you should get a move on is ordering a barrel.
If you go custom it might take that long! And cost almost as much as the Lower/Upper Set.
I would call Wolverine and see what they have for AR10 barrels. The Armalite Stainless is a nice barrel.
Questar is (might) bring these in, ask them if they can source barrels for them as well.
One Shot has the Daniel Defense Rail in stock.
Good Luck
.308's suck up the money pretty quick