Imo every single member of wolf tavern family was wasted. You're even introduced to Garth before you are cait, but gweyrs quest sunsets all of them. Garth is set up similar to sojiro/iwai from persona 5, but has no long term support.
Garrett is one of very few likeable male platonic/romantic characters, has a good character arc of growing as a person, has a unique gauntlet fighting style, you help him with all his regrets and things holding him down, tons of bro content, and now he's just scheduled to be shipped off to mercenaries. Seems perfectly set up to have been a later companion, definitely more than viviane.
Gwyn is caretaker of the entire games children but ends, too. Dialogue wise she's treated mostly as one dimensional or shuts any further dialogue down when being wrote more complex, so she comes off as uh, switching between having developmental issues or being manic/depressive. Had same ero content forever but got a threesome with second best cat farming tool from Temple some time ago so that's cool I guess. Gweyr got a full arc but they decided to write her as an old invalid at the end so she just sits in her rocking chair now. The finale is also handled poorly, been while since I did it, but think it was by tobs? PC was wrote similar to how he was in convocation of mirrors, just suddenly super pretentious and a prick to everyone, handled everything textbook worst way possible, particularly last confrontation with Garth.
I can't write gooder but tons of room for war vignettes from them too, like how kinus are. They always mention little events but they're never shown or vividly described. Have a younger Garth/gweyr/merc npc, play out scenarios from their life, their relationship, gweyr dom action, gweyr wearing that maid outfit they gave jaelyn. Would give Garth/gweyr ero content without breaking their relationship. Kitsune end belt doesn't really have any competition, so maybe after doing a few or a particularly hard one, something like "thanks for listening, kid. This always kept me safe, but I don't need it anymore. You're one of the family now anyway." and you get something like a Grey Wolf belt that cleanses a stun early on PC once a fight or a bonus action once.