It really depends on the situation. Prep time / No prep time. But let me make this clear....ITACHI DOES NOT HAVE KA (even if he did use it, it re-acts to his MS Sharingan, and no-one else in this match has his sharingan. Even if they did, the orders would be "protect Konoha. Real usefull.), AND IZANAMI WOULD BE USELESS IN THIS FIGHT UNLESS USED ON OROCHIMARU, BECAUSE J-MAN AND MINATO ARE NOT EVIL AND THEY ACCEPT THERE ACTIONS. THAT IS HOW YOU BREAK IZANAMI.
If there was prep time Team Frog High Difficulty.
1.) Edo Kages are very strong, even though J-Man and Minato can seal, these are not the push-over Kage in Naruto.
2.) Even though Minato could FTG because of prep, it really wouldn't help against Orochimaru, seeing how he cannot kill Orochimaru with seen techniques. He could kill Itachi straight off the bat.
3.) SM Jiraiya puts his team over the edge due to high reflexes, highest chakra reserves in this match, best variety of summons in this match, and with his summons he can combine deadly jutsu into devistating jutsu. Since prep-time would be allowed in this scenario, he would have Shima and Fukasaku, which could put the Kage in frog song, and J-Man or Minato could seal. Then it would be 2 on 1 advantage Toad.
If no prep time, give it to Team Dark, even though it should be team gray, cause one is nice and one is mean. Med-Difficulty.
1.) Even though Jiraiya would still have the highest chakra reserves, he wouldn't be as great as SM Jiraiya and would take along time to get his summons out. I expect him to be the first one dead, or it might be Itachi.
2.) We have not seen Itachi's Totsuka Blade hit a moving target. I would assume that J-Man and Minato would be moving, and not standing around with there hands in there pants (take that back, I can see Jiraiya doing that.) We have seen his Amaterasu hit people that were moving though, and that is why I would predict J-Man would go down first.
3.) Itachi's Yata Mirror does not protect himself from under-ground attacks, and if Jiraiya has some earth-style technique that can hit him from below, Itachi would be done for. If he has not died at this point by Amaterasu.
4.) If Minato threw an FTG and it got under Itachi's Susano'o, gg Itachi. Minato's superior speed and taijutsu reflexes would win in this CQC. Maybe Itachi could pull off a genjutsu, but unlikely.
5.) By this point, Itachi would have died from chakra depletion, and Orochimaru would come in and kill Minato, based on the fact we have not seen any attack that can hurt Orochimaru from Minato.
Hope this clears things up!