Holy mackerel, nice setup.
Question, why did you go with 2 bends on the intake side of your sump return? It looks like the pump could have fit sitting perpendicular (although sticking out a little) and then you'd only have to worry about one 90 degree bend.
(To be honest I'm not sure about this whole restricting the input of pump, about how far you need to go with that. I had 2 90's on my pump a few years ago but I stepped up the pipe size to be on the safe side, things were fine. But I've seen people not feel right about even using a bushing on a pipe to fit a 1.5" pump input to a 1" bulkead. So I'm not sure where I sit on this one.)
I was gonna comment about how clean the plumbing looks, but then I realized after looking at the skimmer closeup that they must be dryfitted in the first few pictures there.
Nevertheless that is an amazing maze of pipework, good work!!
How does the fuge drain into the sump, I don't see the drain line for that one? Come to think of it .. I don't see the feed line going into the tank, is it capped off for now? I see it start and can follow it along to a point, then suddenly I don't see it anymore.