Itachi has his genjutsu's that he catch every one of the Sannin in from long distance, Amaterasu (which i'm afraid no one apart from Jiraiya in sage mode can dodge), Sasunoo, all his jutsu and amazing Kunai throwing abilities that will put Minato at a huge advantage and is also faster than the 3 sannin.
Minato base speed is faster then all 3 Sannin and adding his FTG to that, there is no way they could touch him.
Minato can take on Jiraiya considering he is faster then Jiraiya and a Rasengan is enough to take out Jiraiya.
Itachi can simply take out Tsunade easily with a swipe of Sasunoo or Amaterasu and he can put Orochimaru in a genjutsu like he already did in the past and cut off his head this time instead of his hand.
Minato base speed is faster then all 3 Sannin and adding his FTG to that, there is no way they could touch him.
Minato can take on Jiraiya considering he is faster then Jiraiya and a Rasengan is enough to take out Jiraiya.
Itachi can simply take out Tsunade easily with a swipe of Sasunoo or Amaterasu and he can put Orochimaru in a genjutsu like he already did in the past and cut off his head this time instead of his hand.