Yeah, sorry guys, but those types of behavior aren't really possible, either. You can't selectively take away a player's powerup or subroutine. (You can only take away all of a player's subroutines.) And there's no way to cancel out a damage effect from a weapon.
At least, not without complex modification of the game's code. It was already very difficult to even get the game to support an extra disc in Multiplayer. It's hard-coded to only support three, and required modifying the game's binary code to get the new fourth disc to work. Given the source code, pretty much anything would be possible. Until then, it requires staying the course of modding the game, with a lot of effort and perseverance.
That being said, there are a number of cool things that have been added recently to the game in v1.2 of the mod, that I haven't shown yet. I think you'll be surprised at some of what has been accomplished, even without source code.