Mechanics
Multiplayer
The definitive answer: Haunted Chocolatier is single-player only.
Confirmed: No Multiplayer
ConcernedApe has stated clearly that Haunted Chocolatier is a strictly single-player action RPG and shopkeeping simulation. There is no co-op, no online, and no local multiplayer.
Why Not?
Unlike Stardew Valley, which added co-op after launch, Barone is designing this game around a solo experience — the ghost-staff shopkeeping and intimate town relationships are built for one player.
Future Possibility?
Nothing has been promised. As with any pre-release title, plans can change — but as of the latest official updates, single-player is the only mode.
Based on official ConcernedApe statements. Fan-made page — not affiliated with ConcernedApe.