Kid Buu absorbs South Kaioshin and turns into Buff Buu.
Buff Buu absorbs Dai Kaioshin and turns into Fat Buu.
Fat Buu and Evil Buu split, Evil Buu still bearing resemblance to Fat Buu ( Cape )
Evil Buu is basically the essence of Kid Buu more than Kid Buu himself.
So Good and Evil re-emerging creates Super Buu, which is what happens when the balance of power having shifted in Kid Buu's favor over Dai Kaioshin.
Essentially it's a battle of Kid Buu vs Dai Kaioshin. We have three forms of Buu to define this scenario.
Original Buu - This is Kid Buu and Buff Buu. Kid Buu maintains his psychotic wild side with a hefty power boost. Just a theory but Buu absorbs Kaioshins by their traits not their power unlike Super Buu and his absorbtion of the Z team.
Dai Kaioshin influenced Buu
1) Fat Buu which Dai Kaioshin has all but defeated Kid Buu in their internal struggle. Fat Buu is capable of being a good being, but his anger boiling up is the essence of Kid Buu underneath it all, his rage, his wildness.
2) Super Buu is made of the same components but now Kid Buu is more dominant, Dai Kaioshin provides Kid Buu with a conscious and he still limits Kid Buu some but for the most part this version of Buu is the best.
He's not completely psycho now that Dai Kaioshin has provided him a conscious, but he retains most of his rawness and power.
Which is why the removal of Good Buu from Super Buu made Super scream " I won't be me!" This new and improved Kid Buu who was capable of clear thought was reverted to his more primal state.
That should clear that up. Complicated shit.