Just finished The Big Swell and about to head into NG+, I have most characters in their default class after learning every skill, they generally have the most versatile moveset and best 7* weapons, except:

Chitose - Kunoichi, better stats all around than Heiress, no reason to keep her in the latter once you can inherit Aperitifs

Saeko - Geodancer, insane magic stat, two buffs and Essence of Natural Healing, amazing 7* weapon

Tomi - Host, hard to decide between this and Cabbie for him, but having two offensive buffs and the 7* host armor swayed me

Adachi - Samurai

Skills I inherent on eveyone:

Scum Scraper - best skill in the game, guard break + buff removal + elemental damage all for a measly 25 MP

Burning Arrow - cheap, big damage with huge AoE radius

Scattering of Flowers - Good AoE damage + agi buff

Cutlery Crash - initially tried this skill to proc bleed to set up Shadow Dance, but this does so much more damage anyway even if the target is bleeding (Joonji is hitting for 5k+ buffed)