And I'm going to apologise in advance for answering your question with more questions and not even answering all of your questions.Also this is Ax. HE DOESN'T PAY ATTENTION TO CLASS! How legit can we take some of his information?
No, he doesn't and while he says "I may not", he admits to not really paying attention. Also, it's taught in school and while we never really get to know about andalite schools, we do know they aren't above propaganda/tarnishing other andalites reputations. Exactly how "Trustworthy" are the andalite schools? Do they only teach the worst-case scenario about sario rips because they think teaching anything else will be devastating? So even if Ax does correctly remember his lessons, how legit are they? Just theories that were hammered into young andalites mind as true?
Like, in book #18: Ax's complete shock of an andalite
If it is taken that the andalites fudged the information about sario rips to only ever teach the worst possible case scenarios, some of the plotholes are filled. We do have canon evidence that the andalites in power aren't above fudging (and outright lying) to the masses so I don't think it's too farfetched to say Sario Rips are one of the things they fudged.