Background: some time ago I melted a spark plug and ate some spark plug ceramic (chicken/egg?). The cause is still not fully determined.
Tiny bit of the lower compression ring missing.
Foreign object damage to skirts in three different places around the piston.
The ring grooves are bent from previous "timing belt failure" events. The top groove is compressed down in two places, making the top ring "stick" a little, as opposed to moving freely in the groove. You can see some of the deformed ring groove in these two pictures.
These ring grooves are what I'm mostly concerned with and the reason I think I should buy a new piston. If the rings didn't stick in the grooves, I'd probably just go with new rings. What do you think?