1. SSJ Vegeta, SSJ Trunks & Piccolo are pretty much the same power level. However Piccolo does not have to transform to achieve the power. Piccolo would win in a fight IMO due to regen and such.
If you look at what I said, I said that even if you argue that Piccolo could beat Super Saiyan Trunks, Piccolo would still be destroyed by Ascended or Ultra Super Saiyan Trunks, so Trunks should be higher up on the list.
2. Gokus statement does not reflect reality.
Oh come on, Goku was ready to crush Piccolo Buu, they're both more than able to figure out who would win the fight by sensing each other's power level. If Goku said he would win and Buu didn't even try to fight, then I'm pretty sure that means Goku was stronger.
Also I'm sure he stated Gohan could beat him, I don't recall him saying 'I can beat you now '.
I remember Goku saying "You're not going to fight me like that are you?" or something along those lines, I'm pretty sure he didn't even mention Gohan.
Gotenks was playing around, he can beat Super Buu without a doubt.
I'm pretty sure Super Buu was the one playing around. Gotenks wasn't taking the fight as seriously as he could have, but he was still trying to win, and was failing. It wasn't until Gohan stepped in that Super Buu started getting a real beating.
Goku stated that Gotenks was stronger than himself.
From what I remember, when Goku and the Supreme Kai saw Gotenks as a Super Saiyan 3, Goku was impressed at how Gotenks was using the form with such ease, but he never said Gotenks was more powerful. Maybe it's different in the manga or something.
4. Fat Buu = Super Buu this is stated in the Manga, there is no reason to debate this one. You have it mixed up Fat Buu split into good & evil. I only ranked Super Buu high coz he can sense ki and has a better physic for combat, he has the exact same power level as Fat Buu. Fat Buu = Innocent Buu + Evil Buu Super Buu = Innocent Buu + Evil Buu
What? Okay, I need to see that part of the manga. From what they said in the anime, Evil Buu was created when Fat Buu got really mad/upset. He was created from all the smoke Fat Buu generated, so the Evil one was a new Buu, not half of the original Buu.
In other words, when Evil Buu then absorbed Fat Buu he then essentially had the power of two Buus. Otherwise, what's so "Super" about Super Buu? He's just a slimmer, more evil version of Fat Buu? ...that's dumb. It was clearly stated that Super Buu was way more powerful than Fat Buu.