Crystal-like Law:

The Crystal Tower dominates the area, rising like an accustory finger pointing at the sky above.
This bastion of sorcery seemingly transcends normal human conceptions, existing in many planes other than this.

A single Wheel? More like a Telescope that stretches all the way back to the Eye of the Anui-El, with Padomaics innumerable along its infinite walls.

Does White Gold's wheel influence only one or all of wheels? Could the Ayleid Wheel be the deceit men were lured to contend for, while the Dominion remains sovereign in all the rest? Have the Aldmer localized the contamination to a single Wheel?

I think that's unlikely, because of http://www.gamesas.com/topic/1369966-i-dont-pretend-to-know-what-love-is-for-everyone/page__view__findpost__p__20696500:

"Imperial Mananaut Jauffre: Was never our intent, old friend. Wouldn’t have the Morbadoon hiss-pissing into our brainpans if it were. This op is Imperial Designate: NUMINIT.
Professor Numinatus: Right then. And is His Majesty safe?
Imperial Mananaut Jauffre: Aye. The Council jill-jaunted him and the whole of the royal family into Mundus Redundant when all of this started."

The Towers are echoes of the Ur-Tower, which was the first spike of unassailable reality. Adamantia must exist in all Wheels, I think, and so the Towers, as echoes of Adamantia, are likely to exist in all Wheels as well.

Why do all the echoes need to be present and exactly the same in all the worlds?

Adamant is the Telescope.

They don't, necessarily. I just think that, based on the information we have, they probably are present in all the worlds. Not exactly the same, though.

If Adamantia is the Telescope, which denotes all Wheels, then aren't its echoes likely to be of the same nature?