There's nothing saying that the choices that carry over can do anything to prevent a certain bunch of events. Nika's conception might occur a year after the events of WiaB. Despite all the theories, Nika can be completely independant from the Zanes, and their interest is of a different nature.
We need to know what choices we CAN make before wondering if we can terminator Nika. I'd laugh if the only choices that carried over were whether you lost the game of darts and got Katie the sweet or spicy chicken
In that scenario, the only thing that changes is dialogue potentially. The core canon stays the same, but the player choices add colour. Maybe we see extra photos on Aurora to add lore/background.
What I do know is that it is so far away that I'm not really worried about the extra immersion by that point. I'll have played and replayed it all many times by then - SG will be too far advanced for me to feel like this is an important thing - currently no decisions in WiaB are really worth porting across. By season 3 maybe? But how much will that change your memories of what you've already played up to season 4 of SG? This kind of thing only makes sense as a director's cut/DLC for completionists because both games are currently being played simultaneously. Ocean would have to stop developing SG and release WiaB finished for this to have a meaningful impact.
The reason we think it's challenging is we all have our own theory of what the canon ending of WiaB is and we don't even know what caused Helen's drama.
Imagine the scene in the book club: Jenna is arguing with Katie about back shots. Maybe you get to chose what sports or who is on your team in WiaB - the dialogue would be changed to reflect who was involved, increasing immersion. Or Willi gets someone pregnant and you see their content via Aurora as a side character with no screen time. Or there are news articles when Nika starts finding out his back story, and they're coloured with the Wiab choices.
The outcome of the Zanes, Reveras and Petrovas creating a shell company is set in canon, Katie, Leia and Willi surviving is set. We can even see that Katie has a knowing history of fiery attitudes with Willi, as Emilia tries goading Katie about Willi. We know Ayua is canon, even if we don't know the details.
Other things could be flexible: for example, the twins could be Gina's if she gets Willi to cuck her boyfriend. Or they could still be Gina's even if she doesn't. That's what I mean by flavour - a lot of the backstory can be rewritten to explain the canon events, with a simple dialogue replacement. Other things might be cameos that are switched on if certain variables are met in WiaB.
I'm looking forward to Nami and Gefritzel's scene, when they take back Noji's house from the mice
