Guys, I'm a genius!
According to my knowledge, Amon is also the Avatar... Remember when Aang died before Katara revived him? After Aang's revival, Amon somehow loses his bending thus wanting to do the same to all. That is why Korra is not getting to her spiritual side as easily, cause it lies with Amon.
the fuck are you talkin bout
aang never "died". And even if he did, your theory is saying that in few minutes that aang was "dead" not only was a new avatar born, but the newly born child KNEW it was in fact the new avatar and also know how to bend. Also going along with your theory, that would make amon around the age of 55-65 (dont feel like doing the math).
He did die in that moment but the whole amon reincarnation theory is not true ..avatar roku even stated in S02E01 that when an avatar is killed in avatar state..he ceases to enter the reincarnation cycle thus eliminating the avatar forever so its impossible for amon to be reincarnated at that moment. My best guess was that amon learnt energy bending from an ancient creature like the lion turtle or a rogue spirit..for his identity its totally up in airs..people are saying yakone and bumi are the most probable but its also probable that hes just a entirely new character but with some connections to past characters.