Both my Return pumps ( ones a spare) are cheapies one came with the tank other from a LFS both rated over 850 to ensure 10x turn over or display with head loss. Looking at sicce pumps or Neptune down the road.
For plumbing all flex hose no fancy pvc thoughts were less 45 degree turns less head pressure loss. Doing over now think having spots for reactors to plumb in might have been worth it but not a requirement.
Skimmer upgraded from a bubble angus curve 5 to a bubble magus curve 7 oversized for tank but wife and ya were overfeeders in beginning so helpful

Will snap pics of underneath for tomorrow.
Dont worry on the fancies you can be successful without apex. Plan it out buy best you can have spares for essentials and it can work fine. Lotsa guys and gals made the mistakes so do your research ask questions happy to help ya avoid our mistakes