The Meaning of Life, the Universe, and Everything.
Afaik, iron golem spawning is affected by door placement, not villager location. So as far as the game is concerned, if your trading hall is within 80 blocks of the iron farm, the village will have more villagers, but not be any different as far as location of doors/spawning location. The difficulty is if you want to have a villager breeder nearby, which requires doors, and could mess up the spawning. If you don't have that, you should be good.