I don't see anything wrong with knee-pads at a Survival event. They are designed to take hits and get beat-up so there's no reason they wouldn't last (no delicate moving parts or cheap rubber there). Scratch 'em on some asphalt and wrap a little tape around 'em if they don't look legit enough for your liking
Personally, I have no idea what kind of chest rig that was or was not supposed to be and think it was fine. That being said, molle is generally considered to be inappropriate for Survival games (several of the load-out threads start with such a claim). Your call.
Aside from the mag pulls and concerns about the gas mask's breath-ability and lens durability, I think that is an excellent load-out.
I am liking what I'm seeing so far (even if I've already seen half of it)..