Fangu
Great Old One
Save the "kinda stupid", this is exactly how I see Reno.There's a very definite fan-created persona for Reno; he's slovenly, lazy, kinda stupid, a bit of a slut, smokes like a chimney, drinks like a fish and swears like a trooper.
I don't think ACC Turks are that far from VII Turks. Keep in mind that the movie needed a source for comic relief, so I guess they developed the "a bit of a funny smart asses" theme from the game into a more clean comic aspect for the movie. There is certain things you got to have in a movie script for it to work, and I can't really see anyone else filling that role in ACC. Yuffie and Cid, and Vincent, also sort of filled that role (and at times Loz and Yazoo), but the rest of the gang are all drama. Cloud and Tifa are all seriousness, and it has to be that way in order for the story to work.
They did a lot of things in ACC that might seem a bit off character or strange, but it's a movie - you've got to do certain things in order to make it work.
Another example is how they managed to make Aerith feel present throughout the whole movie, whether it was through "in Cloud's head" scenes, red ribbons on the VII characters or whatnot. They needed Aerith to be a character in the movie even though she is dead, and I really do feel they managed to pull it off.
PS, I love the Mega Ran "Black Materia" rap about The Turks. Fits them perfectly