I also wanted to know more about Leadership. Is it really useful, and if so, in what cases? After all, it's a wasted slot... So, you'll have to sacrifice something important.

Play for your own enjoyment :) If you want to take Leadership, go ahead! But in real games, and especially in tournaments, it is rarely chosen - it's a very dubious thing.

Also, regarding Luck. It's a good thing for the Necromancer, but is it an alternative to Attack?
Yes. Ghosts will become very good, and their magic resistance will increase, plus -1 to Luck, which is good in the case of a Dread Knight. But still, Luck is a random thing, while Attack always works.

Well, the resistance is clear, but how will this help the ghosts? Are you thinking that they will be missed more often? If so, you are naively mistaken :) In none of the versions of the game has this been the case. Moreover, a long, long time ago, this question was meticulously studied and discussed on various forums, so, alas and alack, missing ghosts is something that depends exclusively on randomness: it is impossible to hit or miss them more than 3 times in a row - this is a fact and it's irrefutable! ;)