Ha, that's generous @lynn.reef.nerd! The plumbing is colorful for sure!
1. I would suggest more flow -- you'll need at least 2 MP40s on each 4' side, and then more of something on the back wall.
2. Electrical isn't mentioned anywhere, and that is pretty important. Since you have walls open, I would STRONGLY recommend another circuit or even two (15 or 20amp) if you can still get wiring through the studs. Lighting can take up an entire circuit once you start adding fill lights, refugium lights - lights in the room itself, etc.. The important thing is that you want REDUNDANT circuits so it one breaker trips, you don't cripple the tank:
Circuit 1:
80W - Return Pump 1
80W - UV?
45W - Skimmer
38W - MP40
38W - MP40
52W - Gyre
300W - Heater
200W - Large LED light
200W - Large LED light
========
1033W
Circuit 2:
80W - Return Pump 2
38W - MP40
38W - MP40
52W - Gyre
300W - Heater
20W - ATO
200W - Large LED light
200W - Large LED light
120 - Refugium light
========
1048W
What if you add more lights? What about random stuff you plug into the wall? A standard 15amp circuit maxes out at 1800W, and you should only run it at 80% max continuous, which is 1440. You have enough headroom with two circuits, but one more wouldn't hurt, if you're able to tie one in from adjoining room.