Not to be a dick, but you said you wanted to make an official ArgonathRPG mod. From what i see, you just found random mods to add them in one pack..
What about getting stuff that are accualy related to Argonath? I have made a modpack with Jim Nail for the biker skins (Angels of Death). change billboards, maybe some updates at PD's and some police officers, i know Vice911(Hank Rafferty) got some sweet mods.
You shouldent add vehicles, these most likley changes the handling in order to keep the car steady wich is not allowed as far i know.