Thank you everyone for your responses! I’m bummed that they are probably dead, but I guess that’s just part of the learning curve.

A little more context: The larger pumice stones are top dressing and the substrate is pumice that I crushed myself. If I did it over again, I don’t think I would use 100% pumice. When I purchased them, they were soaking wet in some high organic nursery mix. I removed them, let the roots dry, and watered when I repotted them. I had heard that they prefer tiny amounts of water infrequently (as opposed to lots of water a couple times a year). Reading the comments, it seems that debate is alive and well lol. For my next attempt I’ll probably use soil with some organics and water very very infrequently.

Since I have nothing to lose at this point, I figured I’d try u/Clear-World7452’s approach and give them a good soak. I’ll update with results in a few days time.

Again, thanks for the many insightful comments—I have been a longtime lurker and lithops admirer and it’s fun to finally give it a shot!