So at the center of the Imperial CIty is White-Gold Tower, which like all towers were designed to stabalize reality.

Towers are usually depicted as the Wheel of Convention turned sideways, and the aldmeri-built towers were supposed to imitate this idea. But then I saw this: http://images.uesp.net/5/57/OB-Imperial_City_Above.jpg

White-Gold is the axel of the wheel itself, rather than the wheel turned sideways. Any significance?

Also, there are 8 districts around White-Gold, and

Yes. http://www.imperial-library.info/content/nu-mantia-intercept

So it makes White-Gold one of the more powerful Towers. Interesting.

EDIT: The Intercept claims that the Ayleids were returning. Foreshadowing for KotN, or is it claiming that the Mythic Dawn are related to the Ayleids?

No, Ada-mantia had that role and also Red Tower.

Rest of Towers should be seen as Walking Ways, to re-reach the divine. White-Gold's main idea (=Main Heresy!) was to harvest creatia directly from oblivion in cooperation with Princes of Oblivion. It just makes me think about where Ayleids are at the moment... In Varla stones, in rocks of White Gold, in lands of Oblivion, in Dreamsleeve? I'd guess answer lies in later two.

Amulet Of Kings in hands of humans, the way i understand it, was turned to work against it's founding idea. To block Daedra from mundus.

Probably both. If I had to guess, Mankar probably used a lot of Ayeleid teachings, magics, and thought-processes to bring about Mehrunes Dagon. I actually haven't played Knights of the Nine yet, unfortunately.

On TVTropes, I saw a comment that basically said "The Thalmor are Ayleids Mk2". Perhaps there was a little prophecy twist going on there?

The Thalmor are more like the Thalmor Mk2. That said, they did have a common "we are elves and thus better than everyone else" mindset.