Return pump(s) for new build (36x30x20)

[H2o2]

well in my boys application I was thinking of putting a check valve in the return line as the sump will be in the basement so then with the soft start it will gradually get the water flowing rather than hammer and I also have dc on my skimmer in the sump at my place so after a power outage u have 10 seconds of ramp time on the skimmer to get going up to speed and in that time my dart pump gets my sump almost back to the correct level so I don't get take crazy overflow in my skimmer cup