got agreement on the spells so what can i fill those three spots with? mana barrier I guess for theme but then what? Influence i suppose for something more subtle than mob mind when its appropriate. hmmm...is the combat sense spell worth knowing? (and owning a sustaining focus for?)
No particular problem with Mob Mind from a gameplay standpoint, in my opinion, other than that the drain is rather high. (It's another one fo those "you're almost certianly taking damage" ones.) If it's a case that the character might not be willing to use that spell because they consider that sort of blatant mind control unethical, then yeah, Influence is a good alternative. It's more like Jedi Mind Trick than Dominate Person, and the drain is low.
Mana Barrier is more versatile than Spirit Zapper, with lower drain.
Fashion is a bit of a head-scratcher for me, since it's basically "change the look of clothes". Sure, there's potential uses for that. (Creating disguises in only the time it takes to make the spell permanent, for one. Or just for fun.) But for just one more box of drain and having to sustain it, you can get Physical Mask and be able to change someone's appearance entirely: clothes, face, metatype, gender, the whole nine yards.
I had looked at Raven and thought it good except that her character as imagined is the exact opposite of a jackass. Of course not all mentor-mage relationships need to be amicable. If a god literally came down to speak to you its rude to be like "no thanks. you're mean." I think ill make the disadvantage the opposite to show this animosity between them. Something like "Willpower + Charisma (3) test to not help someone in need even if dangerous. (Stabilizing a dying corp sec guard for instance)
If the mentor spirit doesn't fit the character, then by all means feel free to switch to a new one. The characterization aspect of a mentor spirit is more important than getting the two best bonuses.
I thought that there was a mentor spirit with a disadvantage like the one you created, but these were the closest I could find. Or you could make your own, if you're the GM.
Dragonslayer gets +2 to Combat spells and +2 to a Social skill, but -1 if they break a promise.
Wise Warrior gets +2 to Combat and Detection spells, but -1 if they act dishonorably.