Absolutely agree with everything you've said. I really enjoyed this episode. It feels like the show is really getting into it's stride and the characters are getting space to grow. Michelle was certainly a bit of a revelation! I actually find her a more likeable character than Tina, who seems a bit too obviously sympathetic and too good to be true in some respects. (I should add the coda that I haven't read the book.)
I definitely agree that it might have helped to see super-confident Ty in the earlier episodes and to have Quinn's case appear later, it just seems a bit back to front as it stands. Jamie's performance was excellent though, and as usual it's the tiny little gestures in the background that really caught my eye. Loved the way he slumped into the seat in the 311 lecture room as if he was ready for a nap ;)
Of all the other characters I find Park the most endearing. All credit to Keong Sim for turning in a low key but really very affecting performance.
PS Hooten just came off as a bit of a diva towards the end.