I just posted two entire pages of flaws in your theories, though... But I can shorten it. Possibility is not probability.

Please read the paragraph after that one, where I clarified what I meant.

And like I said, don't forget C.C.'s final line, which supports this idea. You seem to want to doom anyone with the code to a life of loneliness. While I do agree that it is quite probable, the immortal witch that wished to die for the longest time herself said at the very end that: "The power of kings, known as geass brings one solitude. Not quite accurate, is it?"

Moreover, in your dead Lelouch scenario, you were the one that said that C.C. found happiness in the fact that she 1) found hope, 2) was loved, 3) has loved and lost, and 4) has fond memories that make her genuinely smile like she did in the ending, despite still being immortal. What makes it so far-fetched that an immortal Lelouch will eventually be able to feel the same?