I think unless gohan manned up and actually killed buu with a powerful energy blast, kid buu would win on the fact that he never ran out of energy/tired out. it would become more of a scenario like on namek. ssj goku was weaker than frieza at full power, but because frieza ran out of energy faster, goku gained the upper hand and we all know how that battle ended. so im gonna have to go with kid buu on this one.

Yes I did. There can be many interpretations what stronger means.
It can be based on inteligence, general experience in fighting, power level, abilities and etc. I based my answer on simple power level comparison but also gave my opinion why Kid Buu while being the weakest form is concidered the most dangerous form all three Majins.

And also this +

To end this all.. Majin buu looks like bubble gum.. i want to bite him so badly.

Gohan is strong and kid buu is strong lol they'd both be evenly matched if you ask me

Not true at all. About freezer 100% freezer were not stronger, they were balanced but as you said freezer went out of power fast so goku won. And about boo he can´t regenerate forever, his energy isn´t unlimited (on super boo vs vegetto battle he had problems to regenerate on the end), after some rounds kid boo would stop regenerating.
SSJ3 Goku was balanced with him but same as on freezer batlle, SSJ3 drains too much power while kid boo awesome regenerates (awesome, no unlimited) goku had no chance to win without genkidama.

Kid Buu was his original form.....He absorbed all the other Kai's to become that FAT shit...Which made him weaker

Once goku and vegeta got the good out of him..He became himself which was stronger than ever before....even goku and vegeta said it i beleive

You belive wrong matey. It's actualy stated that his power increased for a few seconds after fatbuu removal, but then plummeted once he became Kid.

The Kia's essentialy gave Buu a conscence. Once the Kai's infulence was removed he became primal again... Pretty much a killing machine.

Is Vegito the most powerful transformation in the DBZ series?

Canon wise yes