While the Australian trailer does explicitly confirm that multiplayer modes will be available, neither the Australian nor Japanese trailer elaborates on if players will be able to transfer Pokémon to this game from other Pokémon titles. The description of the Australian trailer does state "Please note you cannot transfer Pokémon from Game Boy titles in this version.", which may suggest that the original game boy connection functions are present but non-functional, however we'll have to wait until we can get hands on to confirm if other transfer methods may be made available. If these are not present at launch, there is still also a potential that these could be added in as part of a later update to the Nintendo Switch Online app.