I got a couple T-valves laying around......if I can find them in the mess I call a garage now. As far as blockoff's, for the time being Home Depot sells some 3" rubber covers with hose clamps that I used on Moo if the tips are still installed.

(Not really noticeable on my boat, being black and white, so I just leave 'em).
They're in the PVC aisle.
Ray