Itachi, Minato's summonings can be controlled continually by sharingan and put into situations in which he can kill them easily. Itach is already most likely aware of his ability maybe not version two, but Minato has 0 knowledge whatso ever about Itachi. Itachi, who is also versed in the art of fuinjutsu knows that you can place a seal on someone via touch, meaning he'll stay clear from any taijutsu battles with Minato, who he would know is an expert at fuinjutsu.... The deciding factor of this match without a doubt would be genjutsu, Not even going to argue whether Minato would make eye contact.. that will just turn into a never ending debate..... I will argue that Itachi doesn't need Tsukyomi to end this fight, and he can finish it off with his dusk crow ability.. which doesn't require handseals or eyecontact.. something like that will easily put Minato into a comatose state leaving his body susceptible for attack even if for a few seconds... it's an op and broken ability that people fail to take note of, and Minato has literally no counters to it considering he doesn't know of its existence.
As for the brawl between the characters.. once again Itachi would definitely have a general idea of the workings of FTG, as he had known intricate details of the hokages personal life, and has shown that he was quite the studious young lad.. Keeping a safe distance from the ground Kunai and utilizing his skill in shruikenjutsu to keep any ftg 2 kunai away from him as per norm would be the obvious method of defence .... With minato's speed and ability, it's obvious that the majority of itachi's seen ninjutsu and taijutsu would be the totally wrong approach.. He would just be wasting chakra shooting katons and water jutus, something Minato can easily dodge... and we all know Itachi isn't that stupid... The only option he has then on would be genjutsu, an attack you can't dodge...
Summonings on a whole are a bad idea, they are big and or slow and are all definitely incapable dodging an ability like amaterasu.. something which once again, Minato has no knowledge of, nor knows Itachi holds such a technique...