5 mags should do you ok for skirmishes as long as you're using anything other then realcaps. If you're using realcaps you're going to want at least 8 and more like 10 or 12.
As to some sort of facemask, face bleeders happen, and chipped teeth are possible, but alot of airsofters take the risk. Almost no one uses hard masks like paintball masks cause they mess with cheek weld but some use soft balaclavas or wraps or such. It's a judgement call on your part.
As to a good charger. I good affordable one that alot of my team including myself uses is the Universal NPT Smart charger. This guy here
The JG Dragon is just an M4 with an ugly shell. So it is possible with alittle work to make it look like an M4 again. It might be a good backup/loaner but I personally wouldn't count on it for my primary.
(And this one I did write specifically for you. =^_^=)