In a mod that I am in the middle of writing I have taken the idea of the household gods to be a small shrine to the couple of PoM gods that are special / significant / more personal to the household.

This is probably the correct angle to take within the Arcanis universe. Hell, you could even cut the Pantheon in pieces relating to their roles in society, and some do. Recall that there is a marked difference in the importance of the individual Gods in Haina, where if they do not have a military angle the government doesn't officially support them. As such, Saluwe' and Beltine would likely be more of a 'household' god type, while Nier and Illiir would not.