it's non-canon so they might. Honestly it doesn't really matter does it?

probably won't have too many interpersonal relationships between mk characters. seems to be focused on the mk characters scrapping with the dc ones. doubt there will be any scorpion/subzero, or even liu kang/shang antagonisms.

By all indications it seems like placing it between MKII and MK3 has just been a crowd pleaser that lines up roughly with their character choices. As already mentioned -- it isn't contributing to the central storyline.

It if was, however, that'd be pretty neat!
I mean, I'm not sure why you'd put a canonical game in that era, but at least it's a tangible reason for Scorpion to be involved in heroic events, that really goes back and contributes something (to a completely abandoned idea).

Maybe it would contribute to the storyline. Boon has mentioned that there will be alliances. It would be cool if Scorpion helped Sub-Zero, or saved him from some DC threat. And then sorta of teamed up for the rest of the game

I'm pretty sure the whole idea between the game's storyline is that the characters of each universe drop their grudges and join the same team to fight off what they perceive as an invasion from an alternate universe.

So Scorpion and Sub-Zero won't have or need any more reason than that to team up.