So I feel like, some time ago, there was a huge discussion on this, but I want to see some reassurance.

The Khajiit are bound by the Lunar Lattice... but does this mean a http://www.uesp.net/wiki/Lore:Khajiit#Cathay-raht and a http://www.uesp.net/wiki/Lore:Khajiit#Suthay-raht could have a child that ends up being a http://www.uesp.net/wiki/Lore:Khajiit#Pahmar?

Yep. The nature of the child depends on the phase of the moon. Theres a short article about it http://www.imperial-library.info/content/khajiit-physiology-phases-and-forms.

What would the word for that even be? Lunal Subspecial Determinism?

... I may have been doing too much Science recently.