Update 5/7/2019
My C. castaneus colony seem to be doing pretty well in their new home, but I am eager to get them out of their test-tube ASAP. I ordered an 8x8x12 plastic box to create a terrarium for them, which should be coming in the mail any day now. Only three of the workers ever come out to forage, and they are super cautious about everything. They drag food pieces into some of the extra tubes to feed on for extra safety, I guess. They really liked the mealworms I gave them along with dubia roaches.
Last night I was using the restroom and there on the floor was one of the castaneus roaming! I put her back in their container and promptly reapplied fluon. I think some got rubbed off while the colony was being transferred last week. These ants aren't as clumsy as I thought in any case!
They have a bunch of brood in all stages along with a new clump of eggs you can kind of make out to the left in this picture: