A few months ago on twitter, a former animator at Titmouse named Tillie leaked one of the thumbnails for unfinished Hanazuki: Full of Treasures episodes, and a storyboard for season 3 was also leaked too. She also said that the season 2 finale was separated into 2 parts and was going to be epic.
I should also note that there were 8 unfinished episodes for season 2, so it's surprising on how season 3 was already being worked on, despite season 2 being unfinished at that time.