Not quite sure what you're getting at. There were far more et'ada than 12, and Lorkhan was the only one who saw (and purposefully failed at) CHIM. The 12 worlds are mentioned after the creation of the mortal plane, which Lorkhan did not make himself (he was the idea man, Magnus the architect, and everyone else pitched in).
I dug http://daryam.com/monomyth/ up (unfinished, obviously) - it's a comparative timeline of creation.
I dug http://daryam.com/monomyth/ up (unfinished, obviously) - it's a comparative timeline of creation.
I mean we have the cencept of twelve worlds, both in Anuad and Tsaesci Creation Myth. We also have twelve Daedra, the "later-changed-into" ones not included (Malacath, Meridia, Mehrunes Dagon and Sheogorath).
Lorkhan is the only one who saw his Tower, but this not meant other Towers of "I" never exist. For example Julianos and Hermaeus Mora share the concept of knowledge. Maybe the proto-et'Ada of knowledge should be the add up of Julianos and Hermaeus Mora, that Julianos is the Anuic facet of knowledge, while Hermaeus Mora is the Padomaic facet. They are twins as Dragon and Serpent are twins.
By this along with the Dragon-Serpent we have 12 worlds of proto-et'Ada whose Padomiac facet never took part in the Mundex Creation who are later named the 12 Daedra Princes, so that their Anuic facet either became strong enough to have their own echoes of aspects left, who are later named Aedra, or succeeded escaping Mundus, who are later named Magne-Ge. Other et'Ada all died into Mundus and became the ancestors of mortals, because both their anuic and padomaic facet got involved in the creation, yet they are not special as the Dragon-Serpent who is the only one that saw the Tower?