Ok, developed some aspects of the 4 characters:
some are similar to what Fargo posted
Character 1: The Leader - by the book, excellent soldier and tactical leader, but lacks the understanding of the big picture. All about the mission. Uses Sergeant class.
Character 2: kiss ass to Leader. Decent soldier, but has stupid moments. Follows Leader without thinking for himself. Uses m203.
Character 3: "Commando". Excellent soldier, jack of all trades, but doesn't speak much. Complicated character (can be developed whichever way during the season). Uses ALL weapons; a different one each time you see him.
Character 4: Rookie. No clue what's going on. Thinks the whole mission is stupid, very cynical of everything. Uses Rifleman.
as for Insurgent character development, we can have as many as we like, there isn't really a 'squad'. But can generally break em down into two categories: intelligent and crazy stupid. As you might've guessed the crazy stupid kinds will suicide run every single time they see an enemy.
Ok, that's it from my side. If you guys like the idea, help develop it or tweak it.