I Just Want to Be Normal: Zigzagged. She wants to be good at something or wishes her missions from God were something bigger like saving the world, but then gets upset when they interfere with her social life.
I See Dead People: Part of the "talking to God" package. Although according to Rocky and Judith, Joan doesn't see them every time they're around.
Psychic Powers: Her charism "discernment of spirits" is a form of these. It include a vision of Kevin's accidents before the cops came, psychic dreams about the synagogue fire and church vandalism, speaking to God in dreams, and seeing Judith's ghost when she visits Joan.
Mama Bear: "If someone else made those jokes about you, I would scratch their eyes out."
Big Brother Instinct: He gives a fair amount of advice to his younger siblings and offers to roll over anyone who picks on Joan.
Big Brother Instinct: Despite being the youngest, we frequently see him looking out for Joan's best interests, and Kevin gets mad at Luke for taking on the big brother role in "The Devil Made Me Do It."
The Unfavorite: His parents forget his birthday, he's frequently overshadowed by Kevin, and there's a Running Gag especially in the early episodes that no one in the family is actually listening when he talks, to the point that he's shocked when they react to something he's said.