This is certainly an interesting conversation, so I'm going to add my thoughts.
Beginning from a Meta point of view in relation to the ARG, hey, it's a game. They aren't really characters, even in the game, so everything is fine, and we don't need to give ourselves Fridge Horror. That's no fun though, so...
Going a level deeper and thinking at the level of the game, however, things get complex. Assuming first that they are the characters directly taken OUT OF their original works, sending them back may result in some pretty crappy things. But they're just fictional characters, right?
Not so much. Overlaying the Meta-model that Dryu and I created (which is so far our best model, as it has yet to be contradicted) at their level of reality, they think and act just as freely as we do. When Humans on our level write stories, they are bringing into being whole, self-contained universes, the inhabitants of which, if you only observe their level of reality, are technically full beings in their own right. (At least, as long as the story is well written) A character in a story doesn't just do things randomly, he acts according to a character and personality unique to him. Therefore, each character acts according to his own desires and thoughts, just as any of us do. Even if someone on our level of reality created the characters, that changes nothing. Do you think Doyle would completely overhaul Holmes' character halfway through a book with no explanation given whatsoever? Of course not. Regardless of whether we control the characters at this level, we are controlling them TO ACT IN A FREE MANNER. Paradoxical, but true.
However, I'm not as worried as some of you guys seem to be. Actually, I think some of your early theories that are work arounds of this are spot on. After all, if we just launch this ARG over to the other side of the wall, we stabilize the main wall here. After that, a sub-universe for the ARG comes into being, and we retcon the laws of physics in the sub-universe from here so that it can exist in it's current state, i.e. with fictional interacting with humans.
There. Everything solved with ridiculous recursion and confusing paradoxes. My work here is done.
