There's no actual answer to the question, given that the word list can be set inconsistently, so I had to choose _something_ to go off.
The best word list I was able to find is the one hosted by https://www.sbsolver.com/ , but unfortunately they don't distribute it.
I got a somewhat better word list for part 2: https://notes.billmill.org/blog/2024/03/mitzVah_-_the__worst...
But it's still imperfect. However a lot of the words I expected to be invalid have actually been in puzzles before, so it's not easy to guess which are going to be good and which aren't.
edit: there have been puzzles with as few as 16 words before: https://www.sbsolver.com/stats/count/low
edit 2: I modified the program to print puzzles with at least 16 words, and the "worst" puzzles it found with that constraint are:
unbEknown, jawbonE, monadnocK, woRkgRoup, daGlock, moonwalK, confLux, buLLhorn, yOkOzuna, Fraught, hogliKe