Nice looking tank!
In regards to your suction and discharge locations, that's the way most of us do it; Suction and discharge at opposite ends of the tank, for maximum circulation. A healthy, stocked tank is always going to get some debris stirred-up by the inhabitants.
Obviously you don't have a choice with a hang-on-back, they're fixed.
FWIW, my 55g mish-mash planted community tank is setup like yours, except I've got a small Sunsun 302 canister and two AC70s right next to each other. Doing over, I'd have one larger canister on it and maybe a big sponge bubbler as backup.
