Iruka was only going what other people said. "People called him the strongest hokage". Kabuto is also someone who called him the strongest.
Yes but the problem the BIG problem is that we can't confirm who these other people were as well. They were most likely fodders who called hashi a fairy tail. I don't it was the elders because they would know a little about what hashi could do as they are so old. Danzo was even gagging for that hashi dna.
With hashi we know that these people called him a fairy tale like the so6p and we also have official word through madara. And you have to remember kishi writes madara's lines so that is him telling us directly thought madara how it is.
