Ok, so here's my idea: In some places they find that using a special sort of trap called a mink raft is a better way for trapping Mink. Mink, as a mob, would be amazing. Their fur has always been super popular, so it could totally be an awesome drop, they're related to ferrets which people keep as pets so they could be tamable, they could fish up like minnows or something, some new kind of fish which we already know they plan to add in 1.13, and the way they move would translate to Minecraft beautifully. Their AI could easily be a logical next step after rabbits, what with them being small and fast-moving, and I think they produce a strong smell, maybe a gland or something could be a drop with the rarity of a rabbit's foot. You would use it in splash or lingering potion to make yourself or a location smell bad and repel all mobs for like 25 minutes or something. Better than cats, but with the balance of not being permanent.
The mink rafts could be crafted with like wood or something, and placed in rivers in taiga or forest or something, with mink being a rare river spawn. Placing a raft would increase their spawn chances dramatically, and by themselves their speed and small hitbox would make them difficult to reach and kill with sword or arrow. Thus this would necessitate the mink raft, which the mob wood be inexplicably attracted to, maybe you bait it with fish or some hypothetical insect or something. Being some distance away from your trap could also increase chances, or maybe sleeping in a bed. Mink are brown half the year and white the other half, so maybe their fur could change color every 7 in-game days or something, or it could change color based on the biome they're brought to. They could be bred with fish like cats, or maybe only clownfish or something to make it more interesting. No, scratch that, that would be too hard to farm.