Kid Buu Japanese Name. Due to being the positive new reincarnation of the completely evil kid buu his name is a result of reversing buu. Chibi is japanese for small iirc.
Kuzureru bū kara dasshutsu lit. He is the first human reincarnation of kid buu. So there is no official name for this iteration of buu possibly kid buu with dabura absorbed and based on the pattern of some of the previous fan names the character could possibly be referred to as buubura.
Krillin and freeza aren t called kids despite being small in their base forms.
Evil buu or pure evil buu though i often see grey buu or skinny buu and have no complaints about it super buu. Probably started calling him kid buu because most of the games and english localised merchandise did it. But he s been called kid buu as far back as budokai 2 during english localisations of games. Don t thin majin really have any paterns to their names buu was called buu after the saying bippidi boppidy boo babidi was the boppidy part.