Okay, had more time than I thought. Removed the bridge and clipped the strings as close as I could. Found a strong mini screwdriver and pushed it in, began to hammer on the end.
The strings were wedged in so tight they pushed the grommets out!

Unbelievable.
But they're OUT, and the grommets are finally off the strings and back in the bass as they were before. Thanks for the bright ideas!
A side note: D'Addario ball ends are not as large as GHS ball ends. Guess how I know.
