Maybe just schedule the not-intellectually-heavy stuff earlier in the day, if we can't screw up the parents' schedules with a later start time. For example, start school with a study hall (that you can miss if you're so able e.g. if you can drive yourself to school), and let the kids nap. Honestly that would have been a game changer for me, as I never did my homework until the last second.
Getting on my soap box: most important buildings in an educational institution are the library and the sports hall. Healthy mind in healthy body. Dial in formal instruction tactfully. That's really it.