No-one is buried alive but one of the bosses is named Mole Knight, he spends most of his fight digging underground and his entire stage takes place in underground caves.
There are many animal enemies like rats, various fishes, and gryphons that can die by your hand, and one NPC will comment on how he can't wait to see his pet gryphons again after a level where you had to kill them to progress.
There isn’t explicit dog fighting, but there are wolf enemies. Even if you fight them they don’t show any damage or make pained noises, and their defeat just has them disappear the same as any other enemy.
In Plague of Shadows, Plague Knight briefly comments that he feels sick after going down into the lab on the rotating platforms, but he doesn't vomit or mention it again.