"The screen is red on real hardware, this is verified, although some monitors glitch out and strip all red from the image instead. (this happens whenever background colours are used on CPS1 games with said monitors)"
Do you have any information on how this happens? As someone that used to do repair on arcade monitors, I don't understand how this could happen aside from the game PCB itself having a defect that kills the red output only for that scene.
Since you mentioned this I pulled up several real PCB videos of this game, and the only one I've found so far with red background had other PCB glitches happening. All others had black. It does make more sense that way since if you look at the corners of the 3 game selections have black instead of red, assuming to blend with the background.