I assume that you're talking about the Danzo who fought Sasuke meaning no Kotoamatsukami. Now let's be realistic here, nobody gets to use every single tech they have In every battle. To activate Izanagi, Danzo must first remove the bolts on his arm and form a distinct set of seals. He won't get the chance as removing the bolts takes about the same time it took Tobi to beat Fu and Torune. Now let's say he decides to use his fuuton techs to hold off Minato, he still has to form seals for those. Minato can run at him and attack him with Rasengan/kunai not giving him time to form these seals. He'll have to block or dodge, as those are his only real options and neither really matters as if he blocks Minato's kunai, Minato can then mark him as they are now at close range. If he dodges, then Minato simply throws a kunai at him while he retreats, teleport behind him when the kunai flies close enough and finish him. One might argue "Danzo can mark him first" but ask yourself, If Danzo gets that close to Minato(at arms length) isn't he's as good as dead? Minato needs only put a kunai near him and he's finished.
Assuming he gets to form the seals for his fuuton techs, Minato can ST barrier them elsewhere, dodge by throwing a kunai out of the attacks range then employ the strategy above.
Assuming he even gets the chance to summon Baku, the solution is simple;place a marking on the ground manually by hand then let Baku swallow him. After the tapir has swallowed him, it will dispel and then simply teleport back to the marking placed on the ground. Baku can't swallow the ground(the earth really) and this is shown when the floor of the bridge where Sasuke stood and the floor around him wasn't pulled in by the suction. After teleporting back, get Danzo. Another option would be to summon Gamabunta while inside Baku's belly to tear it open with his short sword of burn it open by blasting oil and igniting it with an explosive.
Assuming he does Izanagi, Minato would always be able to get close to him and kill him as he is only capable of repeating the same techs I explained how Minato would counter above. So, in my opinion, without KA, I say Danzo loses.