Minatos regular taijutsu rasengan combo wouldnt be enough per say because he could literally fight with the spikes out and minato would some how have to avoid stabbing himself before landing rasengan (we know rasengan wouldnt break his bones for sure!).
But kimmi wouldnt really have a way of killing minato.lol And vice versa, kimmi heals and has been shown in CM2 to travel through his bomes as if he has no real body!
If minato had Gamabunta, it would be rape, because bunta is just that Damn good! But with juts ftg and rasengan it wouldnt be enough (if you go by actual feats and no hype). But im sure minato has some bs seal to deal with him. (which kishi needs to hurry and show)