Considering this is a marketing promo video being broadcasted for the purpose of convincing people to pre-order content, I STRONGLY doubt any of the silhouettes are meant to troll.
Its a pretty easy strategy IMO, have two clearly visible silhouettes for popular characters to immediately grab your attention, let the other four be just ambiguous enough that someone could get it right, but leave enough room for speculation/hype to build.
Many people began demanding Manta (including myself) when he was first shown as a stage transition, Raiden being a long time MK staple is a guaranteed seller. IMO, makes sense.
As for the rest-
1st from left: Johnny Cage. Looks like just a 'dude' but he's wearing something on his face that can be seen just off from the side of his head. 1 MK guest per pack, so likely Johnny with his shades.
2nd from left: Batwoman. No cape makes this tough to call, but the head ornament/mask seems right. Can't be Catman/Wildcat because those dudes are supposed to pretty swoll and this character is rather slim.
1st from right: Vixen. Heavily hinted by Boon in the past. She's known to have many outfits being a fashion model so she could be wearing just about anything, but those claws are the giveaway.
2nd from right: Killer Croc? Could also be someone in a cape but I don't think its Shazam,; he's more of a shoe-in for Black Adam premium skin. I think this is a big, giant creature, and it would be the only one of that archetype in the DLC roster. They also have a pretty sweet looking model for him in game anyway.
