For me that's a bit too early, might make everything a little stale tasting. Also stuffing has chicken stock so it will be borderline by Thursday. But you can prepare and cube your bread and bag it. And you can saute the onions and celery for the stuffing and refigerate it.

I think you'd be ok doing the candied sweet potatoes now, but the stuffing I'd way until Wednesday. You might need to add a little more liquid to the stuffing when you reheat it.