Part of the problem has to do with the fact kids can be on different schedules in the sense that those up at 5:30 and to care for 6:30 will need a morning nap longer and want to start it earlier and want an earlier lunch than those that sleep till 8 and come to care for 9. It will only be a couple of months before they can move to a better schedule so not worrying so much about lessons with the three year olds that includes you is one way to go. I would rather a mixed up day than deal with crying babies that are hungry and tired.

Experiment with keeping the one child up a few minutes longer each day and putting the others down a few minutes earlier each day and soon they will all be going down the same time in the morning which will put them on more of a similar afternoon schedule too.