So for omega runs, are the rules get to the platform without killing an enemy by any means possible or do you have to agro all the guys or what, and are you allowed to use glitches like clipping through a wall?

i believe you have to spawn the enemy's so in golden you can't do the act 3 skip or in CCC you can't do the other skips but i could be wrong

Every player must touch the end platform before they damage any enemy. You only have to kill the enemies that you spawn, so you can use any skip you want, but it will be an any% run. You can skip the extra spawns in the left room on act 5 of Golden Trophy and still be a glitchless% run.

You don't have to spawn all enemies. You are allowed to use skips. For example, on act 3 of Golden Trophy. You can go through the wall behind you, without spawning the first wave of enemies on that act.

For multiple people does everyone have to touch it before ANYONE does damage to anything?

No, once you as an individual touch the platform you can go attack enemies