I still can't really decide if Akatosh was the first original soul that made time to help the other Et'Ada form, and then helped create mundus, or if all Et'Ada formed first and akatosh only made time after mundus was created to stabilize it. The first would negate the claims of the scriptures you mentioned. Unless it all happened at once. Which would be sort of logical as there was no time for it to hapen any other time. Hm, yes. Perfectly Logical.
1. Grey Mabye. Et'Ada try to be but die.
2. Auri-El/Tall Papa/Akatosh/ comes along and introduces time. The et'Ada become immortal.
3. The Aurbis splits into Atherius filled with Magicka and Oblivion filled with Void.
4. Lorkhan comes up with a plan to create Mundus as a return to the first brush, #1.
5. Mundus is made in the image of the Grey Maybe, the participating et'Ada become mortal again.
6. The creation of Mundus changes et'Ada /creates new Daedra.
7. Aedra duke it out with their mirror images in a phantom war.
8. Aedra depart. End of the Dawn Era.
Going out from this logic - my claims are that the Daedra aren't trying to imitate Mundus for their planes are themselves and represent what they are, believe themselves to be or want other to believe they are. Ok perhaps they might be trying to imitate Mundus. However they already had to have their planes before Mundus was created if my theory is correct. Unless they were swimming the waters of oblivion at the time.
I was referring to Shezarrs song from the Monomyth. Though that may be a self aggrandizing perspective. So yes, imitation isn't a given.
Some might claim that that's impossible because that would mean that the visible planets mean that some Aedra still have their own planes. This is might be true. Consider, Akatosh has his own lower Aedra that don't appear on Nirn except in time of a dragon break. Where are they the rest of the time?
On the Dwemer Orrery the planets orbit Nirn, which would suggest that they (their planets) are part of it.