From Dark and Darker Wiki
I does appear to be those 3 merchants again this season. All 3 still have the cosmetic reward quest on their respective pages. While the rewards are still listed as last season's cosmetics, the quests themselves are updated for this season. Tavern master, for example, requires you to kill ruins golems and more, and the collector now requires a frosted feather which didn't exist last season either.
My guess is that they will be updated with the proper rewards when the quests are released, but if you want the cosmetics then yes, the Tavern Master, Goblin Merchant, and Collector are the 3 you want to focus on. Notably, there are different questlines, so for example the Collector questline that ends in the cosmetic quest isn't available yet.