Lt. Falcon (I think I called him Hawk, before) was really there to fill the "Rebelious Maverick" archetype, which I guess children could identify with, due to his frequent tantrums. He was pretty much a second stringer in the comics after that, since having Duke's brother on the team was kind of "stupid", since the comic was at least trying to be a little gritty.
Other Officers on the Joe team
General "Tomahawk" Abernathy (General Hawk)
General Flagg (Either the man the USS Flagg is named after, or the son/grandson of)
Admiral "Keel Haul" (came with the Flagg, I forget his actual name)
Ace I believe was an officer in the Air Force
Lt. Gorky was an officer in the russian Army I think.
That's all I can think of right now. I'll have to fact check on Yojoe.com