For a manifold, ball valves are fine usually since it's just on or off. If you want more fine tune control, gate valves are nice for that.
With regards to using vynal hose and barbed fittings, I've never had one fail. I've had them on every tank I've had over the past 10+ years.
I just set up a DB 80 and I opted for barb to barb for my drain with a vynal hose and just regular old hose clamps since they aren't submersed. Otherwise there are plastic hose clamps for underwater situations. Granted, hard plumbing looks nicer, but if the time comes and you want to pull your sump out....