Both sound like dream kids But if I had to chose, I would chose the 12 month old that is calm and transitioning well during the program, but cries during naptime. Why? Cause I would move that 12 month old into their own sleeping area or put on some white noise (fan, etc.) and invest in some good quality earplugs. Yup. The 12 month old that does not allow you to move for fear of a meltdown would be much, much worse in my opinion. Bad sleepers can be dealt with, but not being able to carry on with your routine and caring for the other children in your care would be much, much worse.

Good luck. I'm going to be transitioning a 18 month old and 12 month old in the next few weeks, so I may be in the same boat