No, the loader is an "AI" bot. So he'll do all the loading. I'd imagine you don't have to physically move from gunner to commander, but instaswitch between the two, like you would if single tanking and going between driver and MGer.
I doubt they'd model it to this extent, but loading would be slower with the T-34 while traversing the turret, due to the lack of a turret basket, I believe.
I believe the developers have stated that moving from one position to another in a tank will be fully animated, but this is only when moving from one position to a vacant one. Switching control from one crewmen to another will be instantaneous, I think.