With the CC in the locomotive you're only running speaker, coupler, and backup light power to the tender so you're good with the 6 pin. Hopefully Larry is running his Hudson on 072. Straight tether might be an issue on 054 or 042, but 072 and wider and he's fine.
As for these NYC J class Hudsons I can't find any statistics where they are "best". The ATSF 3460 class, Milw F7, and CNW E4s all had more tractive effort, higher boiler PSI, more horsepower, larger drivers, and a higher top speeds. Just because the Js were "prettier" doesn't make them best. Statistically they are not even close .