Even if I tried to make semi-prepared NPC's I would have no idea how to balance them level wise. How many skills points and attribute points at level 6 vs a level 12. And what skills/spells should an NPC such as a healer have at level 6 vs level 12?

All this is in the main campaign with different types at specific levels. A port of them would be a start.
However, this removes some of the fun for me, because I find it tedious to make encounters.

Could you perhaps upload a mod of your different generic NPCs?