There are many questions about humans.

1) It depends on the circumstances, but in general, yes, they can. Humans can have a very good start and a strong late game... Perhaps, in a hypothetical situation where "everyone has one castle, and it's the late game," the human will be stronger than the Necromancer, although it's more complicated with the Orc. Thanks to dark magic, the human has at least decent chances, I would say. 3) Yes. Logistics are extremely useful for everyone. 6) If there are no additional human castles, but there are more than one castle (at least more than two) on the map for each player, you shouldn't play against the Necromancer in the late game. Just don't. 7) If it's not Vittorio, who starts with them, it's not worth it. If it's Vittorio, and there's a mentor, it's worth switching to it towards the end.