Well, there is that map that’s in development, that is where torbjorn’s workshop is. So what’s your asking for my very well happen. As for the other two people that might be involved with that mission, I don’t know.
I mean, there’s nothing saying that they still couldn’t help out torbjorn and Bastion during that particular moment.
There’s nothing saying that the events of zero hero are happening at the exact same moment as what you’re suggesting. It could be at slightly different times. And they easily could meet up with him if they’re using the ship.
Also, maybe someone like Ana and Soldier shows up somehow instead (there’s nothing saying you have to have a tank for PVE, retribution didn’t)
It’s really anybody’s guess. These are supposed to be story based so it really depends on how the developers want the plot of the game to go
I mean, I’m not an Overwatch developer, so I don’t know for sure. But from what we do know about everything, it’s possible. It really just depends on how they want to tell the story.