I considered 4 at least semi-thematic.
On reflection, I want to amplify my previous thanks to Boatman. A number of clues nothing short of brilliant. I neglected to praise clue 2 earlier.
Absence of special instructions is OK by me. I was able to deduce the theme within a reasonable amount of time, and it
is a Prize puzzle after all. :-)
I generally am not overly fond of having to consult Google-generated lists, but that is a not infrequent feature/side effect of themed crosswords. And sometimes educational or entertaining.