Update: They flew away today, June 17. We had five that made it. One sneaked out of its container, found a spot to hide somewhere among our bookcases, cocooned, metamorphosed, and flew about the sunroom this morning until I caught (carefully, delicately) with tongs and let it free outside. We put the rest of the cocoons outside on the gazebo and missed their transformation and departure.
For all our labors, they left us husks of their former selves.