Don’t forget what reshoots means these days. Since most scenes are done with green screen, they don’t have redo everything if they replace a character or a performance. They just need to block the actors the same way, and swap the previous green screened actors with the new ones, keeping all the VFX shot. Easy as pie.
Except that if you’ve seen BTS of the latest SW movies, this isn’t the case. But nonetheless they should be able to pull it off. Rogue One ended up having more soundstage work due to the reshoots.