This is one why I'm hopeful they'll make a Nocturnal pack. It's probably the one dlc idea that I would actually be ok with getting a couple hundred building pieces at the expense of only four animals. They would give us a concrete set and wood texture set (both recolorable) that make the god rays/outside light not come into the building. That we you don't have to dig underground or only play at night. I imagine they would also set up a special blacklight enrichment item for both of the scorpion exhibit boxes, which will make them glow when you enable it (wouldn't work with the regular heat lamps).
A nocturnal house pack would be ok with only four animals because there are already a decent amount of animals that would fit in it, and we will presumably be getting at least one more if the next pack is Asia or Southeast Asia (at the very least a clouded leopard or binturong, hopefully both). But the aardvark, pangolin and dwarf caiman would already fit in very well for instance, so four more animals would bring us up to at least 7. That's actually pretty good for a nocturnal house anyways.