Sorry if what I'm going to say has already been said, but I couldn't find it anywhere..

We are led to believe that the ancient Nords of the late Merethic Era worshipped the dragons and were ruled by a theocracy led by Dragon Priests, yet in most Nord barrows and ruins we see representations of the Aedra through the animal totems.

Did the ancient Nords worship all of these Gods, but perhaps to a lesser degree, while Alduin sort of occupied the spot of 'deus optimus maximus'?

I've been thinking that perhaps the Nords worshipped all of these gods equally at one point, but the dragons fleeing from Akavir arrived and saw a convenient opportunity to lord over the Nords, seeing that they worshipped the dragon totem. I'm thinking that the 'Alduin' we see is the leader of these dragons who then mantled Alduin in trying to pose as him..- Apologies if this sounds silly

While we wait for some wise poster to answer, I'll toss in my own (perhaps incorrect) assumption. I was under the impression that the totem animals were worshipped (as representations of their pantheon of gods) and the Dragon Priests were leaders of a splinter cult/sect of Nordic religion that gained popularity, like the Marukhati Selective IIRC.

All of the totemic gods were worshiped as actual deities, but the Dragon Cult was the principal religious and political entity of the early Atmorans. Perhaps because the Dragons had a more overwhelming and tangible presence than the other animals, or because of the tribute the Cult demanded from the northern humans.

Others were revered almost equally, though. Nords thought a lot of Kyne. When we see the three ancient Tongues using the Elder Scroll to banish Alduin, they appeal to "Sister Hawk" to lend her aid. They also thought very highly of Shor, Stuhn and Mara.