The Pokemon Cramorant is famous for eating, or at least swallowing, other Pokemon. There is a version of it that has a whole Pikachu halfway down its gullet. Other versions of Cramorant have just the tails of nearly swallowed fish Pokemon sticking from its mouth.
In the DLC, the very shark-like Pokemon Sharpedo will actually chase the player when they venture to the ocean. You can ride away from them but if they hit your character, a Pokemon battle starts.
A child is disowned by his father figure, and he feels very betrayed and hurt by this. We find out later that his father figure was using him for his own gain the entire time.
When Pokémon are gigantamaxed, it makes them angry and go berserk. The character Piers is uncomfortable by this and refuses to gigantamax his Pokémon, but the Pokémon themselves seem fine with it.
You can make curry with many types of ingredients, including a few that are made from Pokémon. You can then feed the curry to your Pokémon, even if one of your Pokémon is the same species as the meat used in the curry.
The ocean, lakes, rivers, and ponds are all throughout the map. The item Rotom Bike lets the player ride on water, and water must be crossed for certain tasks.
There's a hospital-esque establishment called the Pokémon center were you go to heal you Pokémon, but no important scenes take place here and it's more of a "checkpoint" than anything else.
No, but a main character essentially has an anxiety spiral throughout the plot which involves a lot of self hatred. I don't think it'd be too upsetting for a kid to see, but this game is fairly realistic in its portrayal of depression and self-confidence issues. While it is implied that the character is improving by the end of the game, it is never fully resolved.
No, and I believe this is the first mainline pokemon game with multiple minor fat characters! None are treated poorly for their bodies (though I think there are still a few trainer classes which act silly and are only made up of larger character models).