The August date for F&WS was mentioned by various trades for a while, but the other two are new.Aaron Couch said:Disney CEO Bob Iger has given a closer look at when upcoming Disney+ shows will be debuting.
August will see the release of The Falcon & The Winter Soldier, Marvel Studios first Disney+ series. That will be followed in October by season two of The Mandalorian, the hit Star Wars show created by Jon Favreau. And in December, Marvel will unveil WandaVision, which stars Elizabeth Olsen and Paul Bettany as Scarlet Witch and Vision, respectively.
Source: The Hollywood Reporter