Before the end of the movie, The Waits family ends up being traumatized by what recently went down on their vacation talk all in a monotone with a few sentences.
There is a scene in which dad is pissed at Joshua and kind of drags him away to his room, mom says in kind of a "oh bother" sort of way "(whatever Dad's name is) don't hit him." Dad shouts and we are given the impression for a moment that he is going to remove his belt to strike Joshua but he's just tightening his belt so he doesn't get hunger pains.
There is a scene where someone is in the process of turning into a plant and most of his face is now covered in tree bark(?). He's not panicing, he's not having trouble breathing.
The main character, Joshua, does not die. However, there is a very graphic dream sequence where he is cut and pierced by trolls, and it contains a lot of blood and surprisingly decent effects for the time and budget of the movie.
Farting and spitting, no, however Joshua does urinate all over a meal. We don't see it happening, we just see him stand on his chair, mess with his pants, and then we cut to everyone throwing away food.
"Are you trying to turn me into a Homo!?" Said by one of the characters writhing in pain after getting testicular trauma from his girlfriend. Not exactly a slur but does carry homophobic connotations.
There isn't really any blood in the movie, it's all green chlorophyll but it would be considered gorey if it were blood red. You do see that branches have grown out of hands and legs but they are poor prosthetics.