1) Forge doesnt have Hooks to attach HUD into a Helmet (Yet, mostly because it isnt suggested or something)
2) NO TO THE MOVING LIGHT, minecraft engine limitation that the IC2 Dev team WON'T solve.
3) For making this, the IC2 dev team would actually have to make a map system for it, dunno if they are willing to do that.
4) Highlight may or may not be possible, dont have much knowleadge of similar systems.
(Also before someone say something stupid like X-ray vision, NO)
Okay, that makes sense. For 2 though, I was already under the impression that moving light was impossible, but wouldn't it be possible to make the game brighter than what is available in the /options/video settings/ menu? And the HUD wouldn't necessarily need to be attached to the helmet, but more of a trigger that occurs when the player wears item x. Of coarse, I'm talking out of my ass here, but possibly useful? All of the features here only need to be viewable client side- the same way you can join a server with Rei's mini-maps and still see everything as intended by the mod even when nobody else has the mod installed.