Seriously at my wits end

If you're absolutely sure it's coming from the pan just get the Permatex ATF/Hyd sealer. Its a red tube specifically for trans pans or diff covers, not the "right stuff" crap in the pressurized can. They don't carry it at Autozone, but Advanced and O'Reilly do (at least here they do).
I had to use it on my Scamps 727. Have never had to use any rtv on a trans pan before lol.