Well Hiruzen was a beast...I could understand the prospect of him loosing here, Danzo does have Izanagi but nothig else, Tobirama does have Edo tensei and an unknown Space and time Technique...he's not beating Hiruzen, Danzo, Kisame, Konan or 2nd Mizukage.....probably not even Tobirama(hype) but the rest I agree
The ones I still think he csn beat:
2nd Mizukage has the ability to effectively hide with that clam....I figure area effect Jutsu on Kakuzu's level would eventually get to him...
I'd imagine earth spear could tank the suicide clone...it has taken explosives without a problem before
Kisame....this one I still think they're equal because of Kisame's chakra absorbing prowess....problem is he uses ONLY water style which Earth style naturally beats...so Earth Spear is effective...also Lightning csn be conducted into water so there is always a chsnce for electrocution
I don't see what Konan has....she uses nothing but paper which isn't breaking s barf as Diamond defense....and the mass paper bomb arsenal was over s long period of prep time....besides he has been seen surviving explosive tags no problem. Clearly fire presents a danger to her as she doused herself in water against the Aburame clan...Kakuzu csn impliment a wind-fire combination.
One thing to note is that in the entirety of the Narutoverse no one surpasses Kakuzu in combat expirience....he has had decades of expirience being 92 years of age...not even Hashirama or Madara were on the field as long as him (though yes they were both far stronger).