Actually yes- in the tree of life (roots) you encounter some characters being tortured by the antagonist. It's not graphic at all and is implied to be a magical/psychological torture. They get freed pretty much immediately.
Some pokemon (including most of the playable characters) look like stylised/ cartoon animals. They all have a lot of expression sprites including sad expressions.
Kind of- the pre-credits story concludes bittersweetly, with the world being saved but the deuterogonist has to leave and there are a lot of loose ends left untied. HOWEVER everything is nicely concluded in the post-credits chapter which is the true ending of the game.
Yes- about 1/3 of the way through the game "Monster Houses" are unlocked and become a regular dungeon feature from here on out. Occasionally, while exploring a mystery dungeon the player can walk into a room and the monster house will activate- the music changes to high intensity jumpscare music and multiple enemies will spawn in, dropping down from the sky. This usually happens in big rooms with a lot of items on the ground.
MAJOR SPOILERS- the second time the player goes up Revalation Mountain, there is a scene where it appears as though the protagonist has been betrayed/ abandonned by their adoptive father. It is later revealed that this character was posessed and forced to do this against his will, but it is still a very shocking and upsetting plot twist.
During the first half of the game the player is stalked by creepy alien-like pokemon. They are a looming threat and the protagonist is very paranoid about them.
Yes, and it's not exactly scary but it is very emotional and sad.
SPOILER WARNING FOR DETAILS: Over the course of the game 5 characters get posessed/ mind controlled by the main antagonist, including a major side character. They are forced to work for the antagonist against their will, culminating in a boss fight against the player. They get freed after this, but they have a lot of guilt and shame over what they were made to do. The protagonist's father figure takes this particularily hard.
Two minor antagonists get kidnapped by a ghost in the summer vacation chapter. In the final chapter, characters fake a kidnapping to lure the protagonist in.
Only one shark pokemon in this generation- Sharpedo. It's not a main character and is extremely rare to find in dungeons. The Gible line is based off land sharks and one is fought as a boss but they do not look like sharks at all imo.
The protagonists plan to run away from home to protect the others, but other characters find out about this plan and they get a proper "Goodbye" scene.
The deuterogonist's dad is pretty strict but never crosses the line into abuse and they reconcile at the end of the game. It's clear that he loves his kid and is just a bit over protective.
Bug-type is one of the pokemon types. Most of them look pretty close to actual bugs. Also, the second boss fight is against bees with needles on their arms.