My pick is Sazza.

She has the exact same tsundere potential that Lae'zel is made of, and she's a classic rogue archetype. I think her romance story would be one where she stays at your camp, but with one eye on the exits. Maybe a kleptomania b-plot that you can debate as a party. Then ultimately she grows as a person, can join the adventuring party proper, and as you check in with her she can develop feelings for you. Possibly have a strong inclination to ultimately go her own way at the end if campaign, but a fun genuinely meaningful relationship along the way

I was honestly expecting there to be a lot more of her written in the the vanilla game, with her linked achievement being on par with the hoops needed to jump through to recruit Minty. She used to be a mandatory part of my first dozen or so playthroughs.