I believe they won't play with any toy because their happiness level is 10. They each have a minion and are usually taking classes at the gym. How do I lower the level of happiness from 10 so they will play with a toy?

Well, you gave yourself the answer why it doesn't work ;) Easiest way is to take the minion away but it will take several hours for the happiness to decrease. Most people who do MD's quest will have one pet without minion for the playing-stuff :)

I wondered if there might be another way.....My pets all like their minions :(

Maybe I'll just have to miss/give up some of the Major Drills quests.

Thank you for the confirmation.