A Shinobi Bout of Friendship - Boruto Episode 27 Reaction

Also: Kagura didn't *have* to kill any classmates. The time of the "Blood Mist" had long passed by the time he went through the academy (he's barely older than Boruto). Pretty sure the Blood Mist had stopped being a thing by the time of Naruto (the OG series).

So as far as Anko getting fat between Shippuden and Boruto: She (in the manga anyway) is specifically mentioned to have an addiction to eating sweets. During her years as an active Jonin this could be worked off just through training and whatnot. But after she became an instructor? It could easily catch up with her. (Think back to every time you've seen her in the anime. She's nearly always eating, even back in OG Naruto iirc)

And, in fact, the name "Anko" means "sweet red bean paste" which is a kind of sweet food, so she was kind of destined to this fate from day one haha.

There was even this page published in the Manga at some point: https://i.imgur.com/2BELYRw.png

the guy with fish gills belongs to the same clan as fish-boy from akatsuki