Light for the Necromancer.

YES, light is absolutely not needed, especially since there are two types of magic. However, with sorcery, you can defeat any mage; just develop a counter-spell, and that's it, although mana runs out quickly, it's worth it. As for leadership, you're right; morale doesn't affect the undead.

Well, after placing dark creatures, you can also bless your own; it won't hurt, or, after placing mines and going into defense, place skin, protection from arrows, and defend yourself.

First, you're suggesting three types of magic, which isn't a good idea, because you'll definitely lose. Second, why protection from arrows? It seems we're talking about dark magic? And there, dispersion is present, and you won't be able to cast many spells there.