Is this the earliest anyone has got their full team in a cover? Yeah, 5 of them are actually a poster, but still.
Also, both Soudo and Shieldmillia have all their Pokémon in the cover. Yamamoto didn't hold back.
And Hop and Beet are in the background. Judging by this and volume 1, it seems the pattern for SwSh volumes will be Soudo and Shieldmillia with their Pokémon in the foreground, and some other character(s) in the background.
I wonder if we'll ever get Gym Leaders in the background, or if that will be reserved for important characters. If it's the latter case, the only other characters that can appear are Mary (Marnie), Rose, Olive (Oleana), MAYBE Nezu (Piers), possibly Sonia, and the royal siblings. And also DLC characters if the DLCs don't get their own arcs. Mary might only show up in a cover when they get to Spikemuth, but I hope she actually appears in volume 3.
Strange Manabu (Marvin) hasn't shown up in a cover yet, despite traveling with them and possibly being an actual main character.
Quick prediction on next covers' backgrounds:
-Volume 3: Mary, and maybe Manabu.
-Volume 4: Rose and Olive.
-Volume 5: Swod and Shildy.
-Volume 6: Eternamax Eternatus instead of a human.
Vol. 3 and 4 predictions could be interchangeable, because Rose shows up in Stow-on-Side.
EDIT: By the way, Yamamoto changed his Twitter banner to part of the cover.