also, there is the problem of beast races and their sub- races .... how does one deal with the moons and hist sap?
Well, given that this is only reported in books - and we know that in-game books can be and sometimes are wrong - they could always say that these were folklore with no basis in reality. Might annoy some people, but it would work.
If they want to stick with those factors, though, the Khajit would be easy enough; just make it so that the next game has planned-out lunar cycles and have the birth affected accordingly. For the Argonians, though, I don't know what they'd do. What do the stories say the effect would be on an Argonian who never had any access to Hist sap?