Finished it yesterday. Excellent season and completely enjoyable. Great music, great storylines (mostly), and great humor.
Speculation about what happened at the end:
spoilers:end of spoilers
Vanya is to blame again. Harlon has her powers now and Reginald now has a great interest in people with powers. Harlon is seen playing with a bird like toy a lot and it was probably a sparrow. Reginald probably acquires Harlon and studies him which leads to the formation of the Sparrow academy. Harlon would be in his 60's by 2019 so I expect we'll see him aged such in S3 and living at the Sparrow Academy.