Hi Louise and Judy,
Louise, since I can't view the card until its approved, I am trying to help through guessing at your dilemma. Here's what I do, when I create a card it usually is because I had one idea in mind for the category of that card. Once that decision is made, I then go search through the categories with that image in mind and make a note of all the other categories it will work in with a change of wording. I usually limit myself to six with varied wording and therefore varied categories (unless it's a sister, aunt, mother kind of thing).
So, yes each card should have a separate category, but only the words you choose will determine whether the reviewers agree to allow into that category. Browsing the categories with the basic image done, I find helps inspire me to create cards that I would not have thought of on my own.
I don't know if I've helped you, or helped answer your questions! I tried though!
Doreen