I'm led to believe that Kiba and Kakuzu are more likely to win.
Hiruzen is a powerful opponent and Karin is good support but I don't think it's quite enough. With two opponents, one being a competent Akatsuki member, and the other being a swift-fighter with a giant dog to accompany him, I'd assume that it's likely enough Karin could be taken out fairly quickly, leaving just Hiruzen. Hiruzen is definitely powerful with the hype accompanying him but, assuming this is the old Hiruzen we see in the main series, he's got much lower stamina and won't be able to keep up for very long. That's a bad liability against an opponent like Kakuzu that must be killed 5 times to defeat. Adding on the fact that Kiba could assist in the fighting, Hiruzen would be very hard-pressed to win, if he can win at all.