There shouldn't be any problems with fluctuating mana, as summons consume mana, and magical luck will simply have a different effect for the Orc.

Regarding the mentor, it's possible that he will be completely removed from the game.

As for the "Livny" skill, it works exactly as described. Skilled racial + "Livny" is 4 perks. I doubt that's better than:
- the combination of skilled darkness + area-of-effect slow (reduces initiative to 30% in a 4x4 area)
- the combination of skilled attack + ranged attack (+30% damage)
- the combination of skilled defense + evasion (-30% damage)