Idk how old your students are, but if I did a butterfly+edible garden, I'd try to keep to edible plants. Lots of options cross over. Borage and calendula attract lots of pollinators and are low maintenance. Even though they are annuals, they readily reseed. Honeysuckle will attract hummingbirds and maypop is a favorite of butterflies. Both vines can get a little unruly, so give them a trellis. Parsley, fennel, oregano, and mint will make sure you are contributing food for butterflies and caterpillars to see all life stages. Set some plants aside that you don't mind being devoured. Day lilies, bee balm, and lavender are edible perennials often visited by butterflies and all three have low maintenance requirements.

Be sure to have the kids, especially the youngest, involved in every stage of the process.

Going to the garden center for the plants and seeds, planting them, pulling weeds and watering, identifying the different birds and bugs, butterflies and moths, earthworms and caterpillars, harvesting the vegetables and herbs, drying the herbs or freezing them, cooking the produce and eating it.

What a wonderful resource.

Be sure to put the fragrant plants where the humans can enjoy the rich smells, also.