Wildcat, the M3A1 would likely be used as a fast town killer or self propelled artillery piece as I said. Imagine getting 59 of the sherman's HE rounds to a town as fast as an M3 can get there.
The SdKfz 251/22 would likely be used as a multi purpose vehicle. It won't be as effective at killing a town as the M3A1, but you have at least some capability to defend yourself. I imagine this being a poor mans T-34, in the sense that it is fast, but isn't really suited to dealing with heavy tanks.
The T48 would likely be used as nothing more than a tank destroyer. I can easily see this being used as an ambush weapon where it would kill a tank or two, and then motor away. It may also be used as a camper since it is small, hard to spot, and is capable killing any tank in the game. It could penetrate 90mm of armor at 1800yds when using APDS (armor percing discarding sabot) rounds. I don't know the ROF, but one would think it would be fairly high given the small size and weight of the shells.
