Looks good. Who needs doors, it'll help the air flow!
It is hard to see the back but you may need a few holes for plumbing and power cords too jk
Heat is a big issue in the sump. I have a return pump, skimmer, refuge light and I have a fan over it to cool it. I replaced my end panels with peg board to allow more air flow.
It might be a little late for you but when I build mine I made a built in water catch, the bottom is water tight and is framed with 2X4s. I don't know how much water it holds but with a flood sensor in it, it has saved the floors a few times. Might be able to add something to it before you set everything up.
One thing I would have added to mine would be a small pull out table to put things on while working on/in the tank.