only one vehicle is really repurposed :c (it's a van)
the other two are just an extra-armored humvee and the respective russian vehicle (but with grenage launchers)
and the crossbow is weird. according to battlelog (which is where I also learned about the dumb vehicles (but hey, I guess the grenade launchers will make those jeep kills a little quicker)), there's actually just a different weapon for the scoped version. instead of an attachment. but for each, there are the same three bolt types, an explosive one like jairo said, a balanced one (has fins for longer range and less drop, apparently), and a ''sonic'' one. it says that the bolt does something to spot people within a ten meter radius. idk if that means ten meters from the point of impact or all along the bolt's path. I guess we'll find that out in december