There is nothing that even suggests that there is a ftg level 3.. that's complete speculation.. 2 was his max ,,
Kabuto is number 1, the only person that can beat him is shishui and danzo, and that's because they have ka.. they can beat almost anyone 1v1
Noone bar so6p and his sons, can defeat kabuto, Edo madara, Edo nagato ,edo itachi , edo muu, etc .. there is no one man that can accomplish that.. not even tobi... Minato would get slaughtered with just 1 edo, aka nagato..
Tobi is next on the list... Minato is not , in no way , defeating 6 bijuu's , nope
no way