The key point to remember is that there is no point to this classification in itself. It's just a tool to analyze and compare different champs and to group relevant champs with similar kits together. A champ being officially sub-class X just means that's how Riot see them, but it's only a starting point, not a final word.
That being said, I was rather disappointed with the last version of the classification, and I disagreed with most of the changes compared to the previous one. So when we disagree on what the starting point even is, that doesn't help discussion... Below, a few case by case comments.
For Olaf and Shyvana, the back and forth between the different versions of the classification suggests to me that the current version just needs another sub-class. Other people that would go with Olaf and Shyv in that new sub-class would be Warwick, Volibear, Trundle, Udyr, etc. I've made a suggestion about that (and some other thing) here: https://docs.google.com/spreadsheets/d/1fSghVIlb1XdodKU0ze_gY4a57qwFFZWtuVX_d3Daryg/
Mundo is very definitely a Juggernaut, this one decision is perfectly sane and sound. He only has soft, single target CC, no way to peel for an ally, and no way to lock-down an enemy team with a big engage. In other words, he lacks all the key strengths of a proper Tank. His contribution to a team is mostly his own damage and not dying. That's what a Juggernaut provides, not a Tank.
(Note that if the additional sub-class I mentioned above was created, he might go there, but in the current system, there is no hesitation, he's clearly more Fighter than Tank, and he is no Diver, so he must be a Juggernaut.)
For the various Marksfolks, I'm more hesitant because I don't know those champs as well but what you've got to keep in mind is that: What do they provide to the team? Not what they look like.
Sure, Quinn "looks like" an ADC. But what will a good Quinn do in a game to get her Victory? Probably NOT stay in the middle of her team, close to her Support and Tank, contrary to "real" ADCs. She won't stay on the flanks either, waiting for an opportunity to jump into the enemy backline, because despite her super high MS, she has no good, free-range mobility like a true Assassin such as Zed, Kata, etc. Instead, she will try to roam, disorganize the enemy team, and hopefully win without ever needing to team-fight. So in the end: it's true that she has elements of both Marksfolk and Assassin, but what she actually does with those elements is neither what an ADC nor what an Assassin do. Her output is clearly different, and she has a truly unique playstyle.
Neither Ashe nor Jhin suprise me being or not being a Catcher, but I couldn't say which one the two most "deserve" it. Maybe Jhin, I agree, but I wouldn't be categorical. But more broadly, Riot tried to differentiate Marksfolks using "hybrid" notations, and I don't think that was a good idea, when all Marksfolks are still mostly here for their damage. Basically, Marksfolks are all here to provide damage+a little something, and the little something helps differentiate them between all Marksfolks, but it is not the main reason you pick them over, say a Mage or a Controller.
And I don't think most ADC play that differently from each others. Not to the point that they need different sub-classes. Ashe and Vayne play differently, but compare them to Ziggs versus Vladimir, and they suddenly look pretty similar.
Jayce, on the other hand, would be a good use of the hybrid notation, IMHO. What's the ouput he provides? Poke at the start of a fight, then he swap form and act as a Diver with weak CC. But he really plays like an Artillery at some points, and like a Diver at some others, not a uniquely different playstyle like Quinn. Jayce as a pure Artillery, though, I'm not convinced.
Cho'gath is an odd beast. I'd qualify him as an unreliable Tank with heavy damage to compensate, except that an unreliable Tank is no good Tank, and a Tank isn't interested in compensatory damage, it's not their job to deal damage. Maybe that's enough to make Cho a unique playstyle, maybe that just means he's outdated, I don't really know. But when you say he's a Warden, compare what he can do to what Poppy or Braum can do, and you'll see that he's not a good Warden.