So it’s actually an 8-handed table, but a 4-way pot, correct?

I think I would personally fold preflop against a UTG open, even if it’s a maniac. KJo is really not a fantastic hand to be flatting EP opens from the HJ, with more people to act behind you. Against maniacs I’d prefer to tighten my preflop ranges and not let them pull me into their game of playing big pots with marginal hands. With hands like KJo, you will really need to trust your hand reading skills which will be tough against maniacs with undefinable / very wide ranges. Playing stronger ranges against aggressive & loose players enables you to not be so affected by possible post-flop errors you might make. It also seems that you are pretty deep in the tournament based on those chip counts, which means ICM plays an even bigger factor here, which makes KJo an even worse candidate for playing in this spot.

As played, I think calling the flop is the only option here. You still have 2 people to act behind you (BTN, BB). You also give the maniac some rope to keep bluffing. I think the turn is also just a call, despite the flush draw coming. A maniac is not folding any flushdraws or straightdraws to your jam anyway (you also have a relevant blocker to those, which polarizes his range even more to either Tx or complete air), and you don’t want to fold out his complete air. So I think the line of simply calling down all 3 streets is optimal here against this particular opponent.