I want to know if it's possible to take the two leads from TWO 80mm case fans and wire them together into one 4-pin molex connecter. If possible, would it change any voltage loads, or anything else?

it i possible, just wire it all together and your done, make sure you put the black wires together and the red off of the fan goes to the yellow on the Molex, ive got my 2 80mm exhaust wired like that and my 92mm intakes too, good luck with em