Okay, so here's what I think. NRS always adds a character or two that no one expects as DLC. For an example: in MKX everyone was begging for Noob, Sindel, Jade, Fujin, Sareena, Rain, Baraka, you get the point. But they decided to add Bo' Rai Cho instead of any of the characters I just listed.
With that being said, Ed did mention how DLC would bring back more fan favorite characters (plural) like the ones they were doing in the base game. We're getting Shang Tsung and I think at LEAST one more Trilogy-era character, but maybe more.
Then of course, guests are a given. We are probably getting two, but three is a possibility as well.
- SHANG TSUNG: Confirmed.
- SINDEL: One of the fight-able NPCs from MKX story mode. Baraka is back, seems that Rain is out, but we still don't know about Sindel. For now, I'm thinking she could be DLC.
- STRYKER: John Cena randomly posted Stryker's render from MK9 a couple months ago. This could be "low request" character that they add, but he would still match with the Trilogy theme AND getting John Cena could make him more interesting to some. Ronda Rousey is already portraying Sonya Blade in the base game, so I don't think it's out of the question for them to get more wrestlers to portray other characters.
- SAREENA: Actually had a fair amount of requests during MKX's lifespan and even showed up during story mode. Could be the 3D-era character. She was only playable in MK Tournament Edition and Armageddon (which pretty much everyone had to be) so I think they could get away with redesigning her quite a bit in comparison to other 3D characters.
- PENNYWISE: IT Chapter 2 is coming out later this year, the first movie was a success, he's owned by WB, NRS always does horror guests, and he could fit well within the Custom Variation system because he can basically turn into and cause hallucinations of anything which opens a lot of moveset potential. He also speaks, so he could have dialogue unlike most (if not all) of the horror guest they have done in the past making him more interesting in comparison.
- SPAWN: I think he's finally happening because the creator of the character said he thinks he's finally on his way, and his toy company is now producing MK toys. If not Spawn, then either Micheal Myers or Terminator.
I don't think we are getting Fujin because I'm pretty sure someone translated a background prop and it says something like "Fuck Fujin" so I don't think NRS cares for him too much. They don't seem to care too much about the 3D era in general, so I think the characters they will bring back are ones that they could easily redesign because maybe they didn't get much attention or something.
I don't think any of the MKX characters will return as DLC, so no Takeda, Kung Jin, or Ferra/Torr. I'm not sure if NRS would move MKX characters from the base game to DLC.
I think Kombat Pack 2 will happen and the line-up will be similar.