It's not exactly a tattoo, but Jin does eventually get a mark denoting her as the warden assigned to protecting Regidrago, it's a series of seven blue dots on her left arm in the pattern of Regidrago's 'eyes'

Balei has a Salandit Tattoo, It’s because she has a Salazzle, no deeper meaning lol

Not yet for Tyler! Later on in his life, he'll get a pair Ho-Oh wings on his back for story reasons

Casey's not a tattoo kind of person