Everyman can do some cool shit...but he's still kind of useless. He uses a chemical he developed to alter every facet of his physical appearance. In that repect he's an ingenious observer as he must articulate every epidermal imperfection of the individual that he's emulating. He can also mimmic any sound he hears, be it mechanical, animal, or most importantly a person's voice. The chemicals that he uses can be imbibed or turned into a vapor and released over his epidermis.
His primary (and only) real weaponry is his trusty gas gun. He uses the gun to weaponize a variety of canistered gases that he takes with him (knock-out, tear gas, etc). His pistol can also launch the gas canisters and act as a grenade launcher that pulls the pin as it's fired.
Everyman's primary use is infiltration and espionage and so he's not exactly an integral part of the Super Powered Society Of America. He's essentially the SuperFriends style Aquaman of the team, he can do a few cool thing, but those things are rarely needed in a super hero team scenario.