If nightfighters were to be added, they should be German and British. You know, the two countries who fought a massive air war at night. Beaufighters, Mosquitoes, Bf110s, Me410s, Ju88s, He219s....
Sorry, but the OP's request is nothing more than "Lets get 20mm cannons on the A-20G" in disguise. There are plenty of quad 20mm fighters in the game right now if that is the most important criteria you have. If flying the A-20 is the most important criteria you have, then fly an A-20 and use its quad .50s.