Isn't giving a summon to an elf a separate topic? Based on the stated goals, it doesn't even relate to this mod, and you're leading me down a rabbit hole.
You yourself said that the chances of capturing schools are part of the project.
You could also give an elf Darkness and argue that it would be good, because there's no point in either the Summoning or Darkness skills.
And it's nonsense to remove the enchanted ballista and enchanted arrow from the elf. Why are you doing this?