Couple of things, this
site sells wires for cheap. Search for Belden. I generally use 12ga, though 16 may be fine for shorter runs. I have all the speakers that you are planning on getting and you’re going to be thrilled. I’ve used and love Onkyo receivers so you’ll be fine with either though I prefer the 602 for the extra channel, surround modes (DTS96/24), power, ect. The only thing that concerns me is this statement:
In reply to:
The EP350 is probably too much unneeded power, right?
Unneeded power? Too much? Huh?
Remember bigger subs are not (only) about louder – it’s about lower. Decide how low you want to go, then find the sub that does that the best (meaning flat response to that number).