Thank you for bringing this up. In line with my earlier comment, I would strongly advise to first concentrate this automated effort on the questions that were cleaned up in a similar automated fashion by SE when the ban was put in place, specifically the two concerted cleanup efforts in February 2018. However, it doesn't need to stop there. But this whole problem is rather multifaceted.
So first of all, of course all the questions locked during that process, deleted or not, can be unlocked, which also opens them up for community moderation again. There is really no reason to keep them locked anymore.
Then all the questions not deleted during that cleanup phase could supposedly be reopened automatically, since the idea back then was to keep them undeleted precisely because they had sufficiently high quality and garnered satisfying answers.
I suppose the questions deleted during that process could also be undeleted (but not reopened...yet). It might be worth undeleting only the ones with positive scores, but if we assume that at the moment of enacting the 2018 cleanup process the questions remaining on the site were good enough for it when ID was tolerated and the rest was deleted earlier anyway, then I suppose they can as well all be undeleted.
Then it already gets tricky. Part of bringing ID questions back was doing so under some form of quality regulation. Now while I see the community is indeed exercising their community moderation tools on the newly asked ID question, there doesn't seem to be much of a codified standard as to which questions are okay and which aren't (which is admittedly hard to find, we knew that already). Under this situation, it's not entirely clear if all the questions should be reopened.
However, this problem is alleviated a bit due to the fact that we also had quality moderation back then. So similar to the deleted questions, we can assume that at the point of enacting the ID question ban, the ones not closed yet were supposedly okay to remain open and might thus also be okay to remain open under whatever current quality standards now.
So to sum this up, I think it would be a good idea to first unlock all the ID questions locked during the past cleanup process. Then definitely reopen all the undeleted ones and at least undelete all the deleted ones. And I guess it would even be reasonable to reopen all the formerly deleted ones, too. So basically just
undo the two cleanup events from February 2018 wholesale, but only on these specific questions...for now.
Then we get to the questions asked after ID questions had been ruled off-topic. Now there could of course have been asked a lot of questions that could be fine under the current quality standards, but there could also have been a lot of bad questions. I would hesitate with injudiciously reopening all the questions closed as ID questions after the topic ban. This does require some genuine judgment and the users willing to engage in this process are already doing that. The questions aren't locked and users have voted to undelete and reopen them in the past.
I do think there could be possibilities to reopen these questions in some kind of controlled automated fashion, but I'd rather you tackle this problem at a later point once you're all clearer on which questions you actually want to see as identification questions. Fortunately, those aren't actually that many questions because the ban was rather effective at putting a halt to the very steady influx of identification questions, so those should be manageable to actually moderate with some proper human judgement. And luckily none of these questions actually run away. Let's face it, most of the people asking these are never going to return and those are often the only people actually helped by answering these questions. Noone dies from putting in some actual work and effort (and thus time) into reopening the proper questions. (Of course this puts up the question what the point of resurrecting all these dead questions actually is anyway, but for the sake of the discussion, I'll try not to ask that ;-)).
And this brings us to the danger in this and why I would strongly advise you to
not to do anything to the questions closed/deleted before the ID ban (or god beware, all the questions tagged identify-this-...).
This community has spent years of work and effort in maintaining this site and cleaning up unwelcome questions. Identification questions have always been a major part of these moderation efforts even when they were still on-topic. The community has come to the conclusion to make these questions on-topic again and we should respect that, together with bringing back some of the past good questions that were inappropriate merely because of falling afoul of that topic ban. However, injudiciously resurrecting all these questions that the site spent over a decade on moderating and cleaning up would be disrespecting and trashing all that work, which is a terrible mistake I implore you not to make out of some reactionary idea that you need to bring back all the ID questions now. Noone, neither god nor the community, can and will sort these out again after this decade of site maintenance has been destroyed. These questions had their chance (they were on-topic back then afterall) and they failed.
I'd like to also make some general remarks on this. As I said earlier, the community has decided to bring these questions back, but it's clear they remain (and will likely remain) a controversial issue and we are far from the community screaming in unison to suddenly undelete and reopen all the terrible ID questions we moderated over the course of the last 13 years. And I hope even the staunchest ID-proponents realize that trashing over a decade of site maintenance is not a good idea.
At the end of the day, we also have to accept the fact that site scope is a living and developing thing, which the reverted ID ban is a good example for. Throughout the history of the site we have questions which were fine in the past but wouldn't survive nowaways if asked anew, or which have been closed as off-topic but would be fine today. Not all of these past questions can (or even should) receive new treatment whenever site scope changes. We can do our best to adapt to new developments in site scope and treat questions coherently, but we neither can nor should rewrite history. In the same way we didn't delete every single ID question when the ban was put in place, we also have to live with the fact that a few good questions that might be okay to ask today might haven gotten lost to time. Maybe if the askers actually still care about them, they'll reask them. If not, we'll get new ones, bet sure we will.
As a personal anecdote, throughout the history of the site I always had a big staple of favourited questions that I feel had been closed unfairly and could be turned into great on-topic questions. And some of them I did manage to bring around, but others I also had to unfavourite, accepting the fact that I might not ever find the time to bring them back or might fail at it. The good thing is, other new great questions took their place. That isn't to say "forget about it, the ID questions are lost forever", but merely that you can't bring back all of them and trying to do so in some broad-stroked automated way is very dangerous and quite simply not actually what the community signed up for when saying that ID questions are on-topic again.
As a closing...closing remark, I was, and still am, rather happy to have mostly disengaged from the moderation and maintenance of this site. I have, however, not entirely given up on it and turned its back towards it. I can't stop anyone from destroying over a decade of the work and effort put into the site and part of stepping down from the moderator position was not having to care about this anymore. I do, however, care enough to at least engage this meta discussion and am glad you brought it up, since it is an important decision that shouldn't be let to fall entirely to disregard or overreaction.
