First of all, thanks to everyone for their comments on this character concept! I went ahead and created a character thread for Eskil where discussion about her build can continue. A few points I can answer here:
Fair enough (and thank you for being clear about it). I'm willing to let Eskil fail, all in good fun.
Both good points. I did catch the Affinities, but the 4- or 5-year difference is huge in this context.
Also fair enough. (Although in my slight defense, it is in the core rulebook. But back-story-wise, it's an extraneous complication at best.)
I think I'll also let this idea go. Eskil would have to be taught a Harnessed Magic spell mastery ability separately for each spell, which seems like a huge contortion in her back story. It would have been fun and conceptually apt, but the character can do without it.