Yes sump, with a fuge, and skimmer. And your right will need less flow to give the skimmer more to pick up things. I just figured with all the/ T splits, elbows, height/foot loss, and maybe installing a manifold would be a lot of back pressure loss. At least around 600gph of loss
What type of pump are you using? You are most likely correct in you're going to be dealing with quite a bit of flow loss, certainly bringing you down below your overflows rated capacity.