I am not so crazy about your colorful chassis (notice the black is out of stock). I don't want to carry a bright red or neon green type of rifle to draw an attention. To me everything has to be black.
BX trigger looks like a nice deal. By the way it doesn't come with pins?
So my shopping list from you will be:
Barrelled receiver (absolutely black!)
Ruger BX Trigger
Receiver pins
Charging handle
Bolt buffer (maybe?)
From somewhere else: Bolt, Chassis (unless you have black, then plus a stock), auto bolt release (maybe)