Re: Mental Illusions: Can attacks look like nothing?
Wow, thats a lotta stuff, lets break it down
1: This would be best handled as an EGO attack, with the special FX being the target thinks they are being hit by an invisible man
2: Im not sure what you're asking on this one, Sounds like you're asking if you attack someone with an Illusory fire, can you mask the 'scene' of the attack so it looks like the victim is still just sitting in the chair. You can do it with a Mental Illusion, stong enough in power to get to the 3x ego level to do actual damage. The "type" of attack (fire/tiger/gun/etc) is irrevelant. You would need a second power of standard Illusions to cover over the scene, with full senses, plus a possible Darkness field 1 Hex vs sound to cover the shouts of the victim. The effect you are asking for is complicated and I dont see it being handled with a single power.
3: This is the easiest one, this is a standard Illusions power use, bought with AOE, radius. It would affect anyone in the AOE with whatever you describe happening, in your siutation above they would all see Kevin getting shot, if you roll was enough to overcome Kevins EGO X3 he would take damage, possibly resulting in a presence attack on the other affected targets.