Viva Piñata Xbox 360 Multiplayer: Not Available in Original Game
Viva Piñata (2006) and Viva Piñata: Trouble in Paradise (2008) on Xbox 360 are single-player only. No local split-screen, no System Link, no Xbox Live multiplayer.
Multiplayer in the Franchise
Viva Piñata: Party Animals (2007, Xbox 360): Mario Party-style mini-game collection. 4-player local + Xbox Live. Not a garden sim.
Viva Piñata (DS): Local wireless (DS-to-DS) for trading piñatas/items.
If You Want Co-op Garden Sim
Stardew Valley (Switch/PC/PS4/Xbox One) — 4-player online co-op farming.
Animal Crossing: New Horizons (Switch) — 8-player online island visits.
Garden Paws (PC/Switch) — co-op shop/ranch.
Original Viva Piñata is a solo masterpiece. Enjoy the tranquility alone.