TY! I'd never heard of Oscularia, TY for turning me onto it. Do you know which one you have? Saw a few diff leaf types on an image search. What a cute plants! Your avatar pic is really pretty, BTW!
I've been on the edge of my seat about the Lithops too, sure every time I go to check on them they'll be mushy, but so far so good. From meshing my yet minor experience with them to the anecdotes and advice out there, the key seems to be to make sure they are dry when cold.
And in general, there's SO much said about succulents and root rot, that I started combating that before adding any plants. The planter is made of wood, so I also don't want it to rot unnecessarily quickly from being too moist (a huge challenge in steamy south AL!) It's coated with urethane, has a TON of holes drilled in the bottom, and is on legs. I cut the sides off of a couple plastic flat-trays that 6-pack plants are sold in, and put those upside-down on the bottom. So in most places, there's a bit of a gap between the soil and the planter, or at least there was. This probably resulted in an uneven surface on the bottom, making it less likely for water to pool. Decomposition of the organic bits in the soil mix will probably lead to those spaces being filled with debris eventually. Whenever the planter does deteriorate, I'll find out!