The top ask implies that in every pnat character, there is just some background homestuck knowledge that they are not entirely conscious of. So their behavior is slightly influenced by Homestuck.

Johnny keeps licking things like Terezi. People fall down the stairs, and someone shouts “It keeps happening.” Max’s “projectence” is like Dave’s misspelling words like “distaction”.

Also, Isaac reads homestuck just to find out how to be cool. So I don’t see him reading it for the plot, but to just take notes from Dave on how to be cool.