MapleLeaves
No offense but according to the key characteristics portrayed by the MC I think a 15 inch wand with Thestral hair core made of Yew rather than Elder would be more appropriate. According to Wikipedia and Wizarding World sites Yew wood is symbolic of Death and Resurrection (reincarnation in this case). Yew wand holders have an inclination towards Dark Arts and are also fierce protectors of loved ones, both of which has been portrayed by the MC. Also Yew wands never choose a mediocre or timid wizard. So the Yew wand is more attuned to the MC than the Elder wood wand according to my opinion.
I don't know but this last part seems a bit unnecessary, like, In the totality of the books, Snape (as a teacher) only appears happy with the disgrace of those he doesn't like, that when he showcases "good" emotions wich is rare. And now he feels some kind of expectancy and seems to throw smiles at people he met in less then a day.