(If this sounds sarcastic or flippant, that isn't my intent): Are you suggesting that disrupting the Order of things—in this case by removing the Coins from mortal circulation with Lasciel's, Ursiel's, and Thorny's in the possession of Mab and Hades—that there will be backlash, and that the Walkers manifesting in our reality represents this backlash?
Also, yes, remember that Hades has both Lasciel and Ursiel; the Gensokwa was killed at the Ice Gate, and Harry didn't retrieve his Coin.
If I understand correctly, that's an interesting idea. I'm not sure how that would be explained if it's the case. Mac says there are three Walkers, and there are three Coins out of mortal hands now. This goes against the idea that Nemesis is He Who Walks Beside, of course, so maybe we'll see the third Walker come out to play soon.
More or less, yep.(forgot about Ursiel there) The coins balance out the swords 30 to 3, but as we've seen in the DF elsewhere most everything has a balance on the leverage. Usually in a tit for tat manor. but what if it's to keep their real counterweight in check, 3 walkers to take on 3 KotC. Other reasoning's that point that way, that the Denarians are basically breeding an atmosphere of apocalyptic potential... actually dispersing the energy from collecting and manifesting all in one spot or giving the walkers a penumbral mirror to cast themselves into reality with, as the Fallen take on the mirroring of all the host's actions themselves.
*I could, by and large wax eloquent about this theory for hours, as it's really the one that ties and binds most of the rest of my theories into one cohesive whole.