Famitsu has recently provided some new information regarding the upcoming Pocket Monsters Best Wishes! season 2.
According to the summary on Famitsu, the gang along with the Shin'ō League Champion Shirona will head to eastern part of the Isshu region, which has many non-Isshu Pokémon populating it. They also encounter Hikari, one of Satoshi's previous traveling companion. Meloetta will later become Satoshi's friend and journey with them.