I still talk to cj and flick for the fish and bug models, celeste for the DIYs/star fragments, and redd for museum stuff or art to hang up in my houses. I'll generally talk to leif and kicks when they're in the plaza cause they're cute, and if I need to buy something from them then it's a bonus. And then for saharah and gulliver it depends on how much time I have and effort I want to put in to the interaction cause both of them take a few minutes to interact with but can give unique and somewhat valuable stuff. I hardly talk to wisp cause I forget to find the rest of his pieces half the time so there's no point, and I don't really know which songs I'm missing right now so I don't really feel a need to talk to KK either.