The model that I've championed in the past is as follows: First, there were ada that participated in creation and those that did not. Then there were those that participated and exited Nirn at the convention and those that did not participate at first but entered at the convention. Exiting left stars and entering left unstars. However, when entering or exiting, each ada left part of themselves on the side that they came from, creating direct counterparts. So, creating a table after the fashion of proweler's,
Creation Enter/Exit ClassYes None EarthbonesYes Exit Aedra/Daedra pairNo None MnemoliNo Enter (?)/Ur-dra pair
There are exactly four unstars forming the Serpent constellation. The heart of the serpent corresponds to Lorkhan/Sheogorath. I believe the three attending unstars correspond to Namira, Vaernima, and Nocturnal. The support for those three come from:
Census of Daedra Lords: "Nocturnal is accorded the title Ur-dra by nearly all the Royalty of Oblivion. As the mother of night, she claims to be an aspect of the original Void itself"
Words of Clan Mother Ahnissi: "Fadomai gave birth to Lorkhaj, the last of her litter, in the Great Darkness. And the Heart of Lorkhaj was filled with the Great Darkness. And when he was born, the Great Darkness knew its name and it was Namiira"
And finally the unique relationship of Vaernima's realm to the dreamsleeve.
Note that sixteen princes, less these four, leaves 12, matching the worlds of creation. It's not hard to find some candidates to fill out the divines to 12 as well - Trinimac/Tsun, Baan Dar, Ius, Phynaster, Ebonarm, Talos, etc.