Fair enough. I'm a fan of reskinning, as you've done in the OP, and I think you've done a good job of it. I'm not seeing anything major I can suggest to really improve the build. Fey Touched might not be a bad feat to consider for some extra "ancient mystical techniques" (and could explain why the old man is so spry!)I appreciate the suggestions, but I rather would not rely on homebrewed stuff. I want to try the class too, after all, and I'm not sure how comfortable the GM is with homebrew stuff.
One thing that is helping is that we are using a fairly generous stat array, and I am taking standard human to boost stats even more. My lowest are in strength and charisma - yes charisma is "good" for a teacher, but we've all met cranky teachers/professors who still were good at their job . So with int magically boosted to 19 (the headband of intellect was my gm's "concession" to the character concept, one I am very grateful for) and a wisdom of 14... I think I'm good
It is a shame, though, that non-spellcasters get steered so hard to Dexterity or Strength by the base classes; mental stat using non-casters is a niche in the game that I wholeheartedly recommend searching up good homebrew for, or just houseruling yourself.