gonna try to pick characters that dont get lots of (positive) fandom attention...
john is a short king
aradia can draw pretty well, she likes to use charcoal
tavros can bake!
sollux makes music online
nepeta has scoliosis and her tail is sewed onto her back brace
kanaya likes yugi-oh
equius is intersex (over-produces testosterone)
gamzee goes stiff and falls over when he's startled
feferi likes legos, especially making her own technic machines
jane thinks piercings are very very cool but is scared to get any herself
i have a ton this is only a glimpse B)