Everybody, all the settings, all the dip switches, all the press tab (yeah, on a PCB) in the world isn't going to help this guy.
The Simpsons 2 player is not the same PCB as The Simpsons 4 player. Same thing with most of those Konami games, they have different boardsets for 2 player and 4 player and you can't romswap them because of different security chips.
In short, he has a 2 player board, and it isn't going to magically become 4 player because it isn't a 4 player board.