sorry, was gone for the week but thanks for your responses guys!
i think i'll order some more jellies and do as ratmosphere suggests.
@jkim, they definitely pupated, and subsequently eclosed in the fall because a bunch of them built their pupal cells such that the pupae were visible through the container walls, and sometime during the late fall, the pupae were no longer present but the shed pupal casing was. i can definitively confirm that they're adults and have been for awhile now, since i gently removed the solidified dirt from their containers to check on them before leaving and all of them are adult beetles that're alive and moving. they just haven't come up to the surface at all.
but yeah, i really appreciate the reassurance. i guess i'll sit tight for a while longer and wait for them to come up of their own accord.