I mean I am willing to bet a pretty penny that is what the devs consider to be the "cannon" ending and how they will manage to get silverhand in the next game.
Honestly in any ending you can bring back Johnny, Including the suicide.
To be fair, Johnny's engram still definitely exists within Mikoshi, since no one said that it cannot be copied. Thing is that it's gonna be hard to have Reeves play Silverhand again and make it make sense. When Johnny's engram takes over V's body, he still has V's voice. And bringing back his engram? Really hard to tie it back with the rest of the story, unless we assume that the canon ending was the one where Johnny went beyond the Blackwall and we somehow encounter him in Cyberspace again. or, again, we could have a prequel or a prequel sequence that would show us what was actually going on when the Night City Holocaust happened.
The point is that Keanu wants to play the role again, mocap and everything, because he enjoyed it. Actor things, sometimes it really clicks for them. The real challenge will be writing in a sequence where he can play Silverhand in full.
realistically theyre going to ask the player which choices they made and the ending they picked and then have the game adjust for said factors affecting it
Realistically they'll just look into your save folder to pull that data from your 2077 playthrough. This was common practice in the PS2 era, for example getting a cash bonus in Most Wanted when an Underground 2 save was detected so you could start off with a Golf. On Windows it's just a matter of looking into the usual data paths to see if anything's there.
As for the whole "V and Jackie are idiots" discussion, in all fairness, the entire heist plan was basically flawless from start to finish, but no one could've accounted for the fact that on this exact day, in this exact moment, not only did Saburo fucking Arasaka decide to pay Yorinobu a visit, but Yorinobu offed the old cunt as well. That event alone was what resulted in everything going tits up. If not for that, V and Jackie would get out scot free, sell the Relic to Evelyn, Evelyn would then get sold off to the Scavs anyways, Voodoo Boys would likely get fried by Alt anyways if they managed to fuck with Johnny's engram to get to her, then V and Jackie would go on as somewhat known mercs. Not big league legends, but they'd do alright. Obviously, not only would it neuter the entire storyline, it would neuter the entirety of PL as well since So Mi likely wouldn't crash Space Force One if V wasn't there to help her in her plan, nor would he be in Pacifica for that to happen.
Speaking of, only today when I eyeballed all the crap in a tech store I realized the meaning of the DLC's title when I looked at the adverts for the Switch 2 version. In Polish it's "Widmo Wolności", which translates more as "Phantom of Freedom". When I rephrased it like that it clicked. Reed, Alex and Song all sought freedom from the FIA. Song also sought freedom from the Blackwall. And V sought freedom from the Relic. But in the end, this freedom was illusionary, as the grasp of FIA on Reed, Alex and Song was inescapable, as was the grasp of the Blackwall on Song and the grasps of the Relic on V.
Anyways, think I'm gonna sperg about the cars in the game at some point later on.