I've done one of these before, but I'm not sure as to how the one I have done and the one you are running are alike and different.
Here are some of the ones I've seen before:
Pointman: Proficient with close range weapons, including shotguns & pistols, and fairly skilled in the usage of unarmed combat, including CQC, martial arts, and other fighting styles with lethal capabilities. Usually the ballsiest and toughest of your squad or fireteam.
Specialist: Proficient with explosives, including grenades, mines, traps, etc. Usually is someone elses' hip-man, carrying their essentials, and in turn recieves cover from that person when planting or deploying unconventional weapondry. Can't carry as much as a Hip-man, but has the knowledge of making and deploying explosives.
Hip-man: Usually another persons' partner, holding consistantly more ammo, health, or other essentials. Is proficient with a pistol, PDW, (Personal Defense Weapon) or other small, lightweight weapons. Much more fitting than a Specialist, but lack of explosives can be limiting.
*glances at topics' dates*
Well, that sucks. This looked kinda fun.