Evil Buu/Chibi Buu...

[Horgus]

Ah, I see what you mean. I think by that point the Dai Rou Kaioshin and Northern Kaioshin had become irreversibly ingrained in Mr Buu. Maybe that happens after someone's been part of Buu for a long time? Just an idea.

Buu digested them.

He was sealed away for thousands of years, it's not inconceivable.

[Bussani]

I love the words 'not inconceivable' for some reason.

[Wojak]

Ah, I see what you mean. I think by that point the Dai Rou Kaioshin and Northern Kaioshin had become irreversibly ingrained in Mr Buu. Maybe that happens after someone's been part of Buu for a long time? Just an idea.

Buu digested them.

He was sealed away for thousands of years, it's not inconceivable.

The question is, are they in any kind of conciousness when in Buu's stomach? Or in a coma? Did Gohan et. al. remember even a thing after being released?

[Terra-jin]

Incidentally, my very first topic was about this subject. The main point I made there is that the two Buus share a spiritual link (like Kami & Piccolo), through which Evil Buu remained under some influence of the absorbed Kaioshin. When Vegeta rips out Mr. Buu, this link is broken and Evil Buu is no longer linked to the Kaioshin in any way. Hence, the new Kid Buu is actually the evil half of the original Kid Buu (although you wonder what's the difference when original Kid Buu was already pure evil).

Ask yourself this: what would Mr. Buu turn into if the Kaioshin are ripped out (presuming they weren't digested by then)?

[Metrite]

Ask yourself this: what would Mr. Buu turn into if the Kaioshin are ripped out (presuming they weren't digested by then)?

We don't know enough about Buu to know if they could still be in there or not. But if they were and were removed then he'd turn into Pure Buu, again. That's the official term for The original Buu for a reason. What you said sounds just like what I've always figured, that there was only one Buu in existence until the evil one became a separate entity, leaving the other as his old self(hence why it was brought up that he could give rise to the evil Buu, again).

[Terra-jin]

But if all of Kid Buu's evil went to the one that's killed by Goku, this new Pure Buu wouldn't have any of that evil (or power).
To tackle this problem, we would have to define exactly what happens when a person splits his good and evil side. Obviously, his good and evil traits would be separated, but what about his neutral characteristics? And how much power would go to either side?

I think that the neutral characteristics are shared by both sides. This can be seen in that both Mr. Buu and Evil Buu liked to eat. They were also both very playful and yearned for good fights.
As for his power, I think the amount of good, evil and neutral power of a being is proportional to the dominance of his respective characteristics. For instance, Kid Buu was very strongly evil, which is why he would have more evil power than neutral power.

Half of this neutral power was left inside Mr. Buu when he separated. This means that the new Kid Buu is actually a little bit weaker than his ancient counterpart. Furthermore, the hypothetical form we've been talking about would have only that amount of neutral power. No evil power because that went to the evil Buus, and no good power because any good in Buu was there because of the Kaioshin.
The only problem here is that Mr. Buu was said to be able to produce another evil Buu, but that seems unlikely because there was no evil left in him at that point (at least not as much as Kid Buu).

Yeah I may be taking this whole thing too seriously, but I'm just that intrigued by Buu's character.

[Metrite]

But if all of Kid Buu's evil went to the one that's killed by Goku, this new Pure Buu wouldn't have any of that evil (or power).

The reason he's pure Buu is because that's what you get when you have Buu and nothing but. Every change in Buu from the original, including his personality, came from the changes caused by absorption. That's why The evil Buu freaked and said, "I won't be me, anymore!" The same would apply to Good Buu. The Pure Buu that they fought was the exact same thing that Buu started out as(just Buu), and if Good Buu could have the ones he absorbed removed(which he would likewise do anything to prevent, as not to end his existence) we'd have another pure Buu since that's what a Buu becomes when there's nothing in it. Good Buu is technically a different character, his good/evil/personality has no relation to Pure Buu. The evil Buu he created was just a manifestation of his own rage. And the evil one changed back exactly as Good Buu would when he had everbody removed because he was still the same person(hence, "I won't be me, anymore!"). That only leaves the Good Buu who, in order to still exist, could only be back to the way he was without dividing, which is why it would be possible for him to again do so.

[Terra-jin]

That means that first there was only one Pure Buu, but after the split there were two. Surely they would be two halves, instead of two complete Buus? By half I mean that they divided their power and spirit. Power, at least, should be quantifiable. Spirit might be another thing, but don't you think it's strange that a purely good being could produce a purely evil being?

With the old Fat Buu it was different, since he was evil (albeit suppressed) as well as good. The suppressed evil was transferred to Evil Buu, who then revert to Kid Buu, this time again with his unsuppressed evil. But that evil went away from Good Buu, there's no way he could produce another evil being.
Or, if you say that not all his evil was transferred: OK, but then evil Kid Buu would be less evil than his ancient counterpart and Good Buu wouldn't reach that level of evil, either.

Here another way to look at it. What would happen when Pure Buu separates his good and evil? There would be a side that inherits all the evil and a side that inherits all the good in Pure Buu. However, since he was already pure evil, the hypothetical good side would just be neutral.

[Metrite]

Seeing how pure Buu isn't related to the other Buu's good or evil(Kaioshin merely refers to him as being the very essence of evil due to the way it acts), it's just a pure Buu, it would be what you have anytime you have a Buu with nothing in it. Since the evil Buu was the result of the other Buu's rage, and the other Buu can only be back to his old unsplit self again to still exist, making two completely separate Buus(meaning the other would also become a pure Buu if his absorptions are removable), it means he could repeat what happened if such circumstances repeated.