Seven Pokémon had been added through in-game events by Pokémon Pokopia version 2.0.0.
The event additions formed one part of the game’s expanded roster. Version 2.0.0 listed 357 available Pokémon in total, including the original 300, 50 introduced through the Bubbly Basin downloadable content, and seven introduced through in-game events.
This breakdown shows why the overall total cannot be calculated by looking only at the DLC. The Bubbly Basin content and the event Pokémon were separate sources of additions, even though both contributed to the post-launch Pokédex.
The number seven is therefore a content-history figure rather than a count of all Pokémon encountered during a single event. It describes the cumulative event additions recorded by version 2.0.0. Players comparing launch data with the updated roster should keep those categories separate.