The problem with the Londo stuff is that it's hard for us to respond without getting into spoilers. Kirk, I'm gonna reply one more time, not to be argumentative or anything, but just in that hope that you'll be able to enjoy this great arc of the show. If not, well, again lets just revisit it later on.
what will happen to him specifically (who he'll ally with, wether he will redeem himself or die a tool of the shadows) has been definitive answered.
Hmm, see, it really hasn't. You only think it has. I'm gonna put the next part in a spoiler tag. It's not super specific or anything, but you may still want to hold off on it. Your choice.
And that's the last thing I'll say about it for now.