Coaster brakes are fine. Run what you want.

Acquire hub, regrease, looseball it and have fun. It will spin just fine. We used to have gravity races in the local parkade and I won all the time over my freewheel buddies. My looseball coaster was silky smooth.

You have been able to buy coaster deepV on ebay for some time now. It's my next dumpster build for rain riding.