I just posted a long reply and it went --poof--...arghhhh.
Anyway, your diagram is much better than I could do.
I would hesitate to put the pump(s) in the back corner. IMO, it would be much better to use one small Sequence pump externally with a manifold and mount it with flexible PVC to eliminate corners.
If you come out here, with enough notice, I can take you on a multiple tank tour to see great systems run by experienced reefers. I got a mentor early on and we still talk reefs to this day. You are welcome to PM me if our discussion takes your thread off-topic. I don't want to bore the pic hounds you know.
It appears you have prior experience and that gives you a leg up, but I would try and visit as many aquariums as possible, taking notes to compare and make decisions. If you build a matrix in a spread sheet, then you can quanitify your findings.
Plus, really getting in touch with what you want to keep, and your overall reef keeping philosophy will help you make better decisions, much like a company mission statement.
Sorry for the jumbled post, but I am trying to remember what I wrote before.