I have this all done, except for the middle cell of 20, which is driving me up the wall. For a long time, I had what I felt to be a most reasonable answer for 21, despite its non-appearance in either my dictionary or online - it emerged from the clue, and just seemed right.
The theme was cleverly done, and I happened to be half-watching a relevant film of TPTV while I was doing it. So it goes.