Do orange and grey! Red is cool but cliche.
I like your plan.
Dremmels are handy to have, though I don't have my own yet.
Cardboard: you making your own helmet? I made mine out of cardboard and bondo/fiberglassed it. It's been pretty easy and not too expensive.
I did trash can too. Watch out for hot plastic: it hurts. But it's a pretty simple method.
Sandpaper is something else you'll want to get, especially if you do trashcan and cardboard/bondo helmet.
Good luck!