Mission accomplished! I remove the wipe jamming up the black valve, then ended up wedging to cut to proper length 1x2s between the tanks to get another 3/4" of room to get the Y fitting and valve assemblies into place (in one piece). Following advice I received on rv.net, I picked up two 6" round hvac sheet metal duct dampers (round disks) to act as blinds to get the valve flanges lined up with tank flanges, then gently pulled out the dampers so as not to disrupt or curl the flange seals/o-rings.
I filled the tanks to capacity to test for leaks, success. Both valves work, seamlessly.
Today I scored a large piece of black Chloroplast from a sign shop I do business with. Now alll I have to do is button up the hole I made in the belly.
Moral of the story, make sure foreign objects including baby wipes do not find their way into the toilet.
Fwiw- the only insulation the tanks have from the elements is the thin piece of Chloroplast underbelly covering. There is about 2" fiberglass insulation sandwiched between the sub floor and a black fabric material above the tanks. Polar package my foot.
I am sure I saved myself at least $500 doing this myself. Not to mention my black tank is as clean as it ever will be.
Thanks for the help and suggestions.
