Ok, now that I have some time:
The best weapon on that list overall is the StG44, followed by the FG42. Note that neither of those are smgs. The StG is an assault rifle, the FG42 a battle rifle / light machine gun. Likewise the VG45 is an automatic carbine. A submachinegun uses pistol ammunition, not intermediate rounds or rifle rounds.
As for submachineguns, there are essentially two different ammo types: .45 and 9mm or below. The .45 do more damage but are harder to control, the 9mm are a bit better over medium range, but deal less damage.
The overall best smg is the Finnish suomi: It uses 9mm ammo from a huge drum mag and is relatively accurate and easy to control. Just by the numbers there is nothing quite as good. Honorable mentions go to the Russian smgs and the Beretta M38, which combines the advantages of 9mm with slightly above average mag size.
The .45 smgs are not quite as good, at least for my playstyle, that being said, the Thompsons are generally fine, even though I find the earlier models hard to use with ironsights because the sight picture is unclear. The M3 Greasegun is the worst imo. It is easy to control for a .45 gun, but the slow rate of fire means you always feel outgunned. With an smg I want to spray down the enemy quickly.