What skills should Necromancers take when facing Orcs on a very large map?

Here, focusing on leveling up only one Necropolis hero is a waste. Necropolis is perhaps the only faction where it is beneficial to level up several heroes. Firstly, you can choose the most suitable one; secondly, and more importantly, it increases the number of skill points. Thirdly, you can level up diplomacy for the second hero and collect neutral creatures.