I'm pretty sure they won't be able to restore jack squat.
I think they're just stumped on how they should compensate for the deleted chars and lost progress/cash. How will they even figure out who the players are that lost stuff?

I think R* just needs to admit they ****ed up and get it over with.
I'm pretty sure getting online and playing is not an issue anymore. Just compensate the players for this snafu and roll in new content.