This was obviously retconned. Both of the
Nyoninzos are stated to be mystical objects that hold knowledge of the Hokuto Sōke and Hokuto Shinken from millennia past. And both serve the same purpose
"this was obviously retconned" is not an argument. Prove it. That's a wiki article, it doesn't matter
Koryu explicitly that each one could be a successor in their own right.
and still says that
all of the three put together made Hokuto "the strongest it's ever been", also, prove Koryu knew of Kasumi and how strong he was
No. you are excluding the fact the both Buronson and Hara said that Ken is the strongest man in Hokuto history period. and it was from the oficial Fist of the North Star X Fist of the Blue Sky Guidebook. that already gives more credibility to Kenshiro. also Kaioh is much stronger and deadlier than Liu Zongwu
using a second hand account from a forum of a guide nobody knows anything about is not valid, especially when the translation is nigh unintellegible. Get a copy of the book, have it translated, and then maybe we can have a talk about that. Kaioh is deadlier than Liu? Based on what exactly? And you really wanna go on about word of god from guides?
the Sekimatsu Haou Retsuden guide has prime Ryuken on the same level as Kaioh and End of Series Ken; the manga itself>guides and WOG regardless
False equivalence Colonel did not master Hokuto, while Raoh did it, so he's much stronger than him. And i only used the fact that Raoh mastered more martial arts than Ken and Kasumi, not to say that he was more skilled than them, but just to show that he is a very versatile fighter.
Which is irrelevant, I don't understand why you'd bring up him mastering a bunch of fodder martial arts when talking about him surpassing the power of Hokuto
This is obvious a headcanon, Kasumi never used Musou Tensei in any of his fights, he never even mentions anything about it, the only time he "used" Musou Tensei he was not even conscious, and when he wake up, he didn't even fully remember what happened, he only seemed to have a vague recollection of it (unless you count with the Regenesis anime) His Musou Tensei did not even looked similar to the real MT, it could very well be a incomplete version.
The only headcanon I see here is yours, tell me, how could Kasumi have obtained "the fullest for of Hokuto" without having mastered Musou Tensei? Him not using it is not an argument, he has yet to fight anyone who pushes him to go all out, let alone use Musou Tensei; by the same logic, can you show me Ken using Soryu Tenha? No? Must mean Ken never mastered that move.
And Kasumi's statement about obtaining the fullest form of Hokuto Shinken does not automatic means that he has MT, and is possibly a Hyperbole, since only those who understands and embraces the true nature of sorrow and loss can awaken Musou Tensei, and i don't think Kasumi qualifies for Musou Tensei. He hasn't experienced nearly as much deep sadness as Ken. In fact I'd go so far as to say he's had a fairly tragedy free life, acquaintances and rivals die sure, but his close friends and wife are all alive and well. He probably know Musou Tensei, but that doesn't mean that he master it (at least for now)
Also you (Now) seem to disergard the Raoh statement, but at the same time you seem to take any statement about Kasumi at face value
none of this matters, it's your word against an omniscient being in the series, you not thinking that Kasumi has the prerequisites to obtain Musou Tensei doesn't matter. It's not a matter of "taking at face value", it's a very simple, straight forward statement with next to no context to it, so, unless you wanna prove the taoist wrong, no amount of "i think" and "maybe it's an hyperbole" will change annything.
I don't disregard Raoh's statements, i actually look at the context and recognize the fact that they were written before Kasumi was a thing, and we know for a fact that Buronson never planned ahead, so it's not like you could say that they already had his character in mind when writing that. the REvive statement is blatantly unusable since it's a secondary source (a game) contraddicting the main source (the manga).