Ah, this is my situation! I am using hybrid questions.
After a little experimentation, I found that I can convert the .jqz source files from question-type 3 to question-type 2 and then import them into Moodle as short answer quiz questions.
The Moodle short-answer quiz does not seem to me to be as versatile, however, as the Hot Potatoes hybrid question. So I probably will not leave the Hotpot format for these quizzes.
Thanks for your help, Gordon!