he's very flexible and won't try to stop players who want to try less conventional combos. it's maybe not the easiest/quickest/most sensible way to run a game, but he thinks if he says 'no' to a lot of stuff then he's saying he isn't capable of making it work, and THAT JUST SOUNDS LIKE BEING A GIANT WUSS. so he'd have taken the n.g. necromancer as a challenge to make it work narratively/etc.

in conclusion

yes ennis be the goodest necromancer you can be