DIPPER'S shadow is going to be calling him out on his insecurities about how he relies on helping his friends out with their schoolwork and other such things in order to feel better about himself, and the satisfaction he feels when they have to rely on him. With so many of them being gifted/talented he often feels left behind and thus there's the lingering self doubt that maybe they don't need him as much as he thinks they do.

His shadow watchers are MABEL, RAZ and NORMAN, considering they're the people he currently feels comfortable around and the ones he feels this strongly towards and he recently offered to help Raz with his potions work, which could be seen as a catalyst for his feelings on the matter.

ROXAS will be seeing RAPUNZEL'S shadow as will MARCIE be seeing BONNIE'S, but I'm always up for them seeing other people's as well or helping out in any way.