how far back will the retcon go?

Because they've said they're ignoring the finale so that Will & Grace aren't parents. But if they're wanting to make them un-parents, they have to get rid of the whole storyline about Grace being pregnant at all, which takes up roughly the last half of Season 8. And I know it's a sitcom and so continuity probably isn't their biggest concern, but her pregnancy had a butterfly effect on other storylines certainly. I mean whatever, can look past it and just enjoy the ride, but I'm basically wondering if they'll just do away with a huge chunk of Season 8, or keep those events in the canon but just pretend Grace was never even pregnant.