Yeah. That timeline is very fishy. (you don't need 10K or even a login to see it)

The deleted extra answer appears to be an accidental double-post. This is rare on Stack Exchange, but it does happen. I wouldn't worry about it.

Here's an idea that can speed up this process: Let users edit questions with the tag, one after another, by automatically going to the next question once the current question's edit has been submitted, through a special editing page accessible from the tag page. The system would queue and complete the edits at the desired interval as the user works on editing other questions.

Unfortunately, the only way this could happen is if a Stack Exchange developer manually edited the database to achieve the result you intend. I don't think they would do this, sadly.

Thanks :) I've a long history of fighting spam on Super User. Also, #CaligulaTrump :P

The site's built-in search engine is powerful enough to do this easily – there's no need to use SEDE. You can search for whole phrases by enclosing them in double quotes and use parameters like closed:0 to isolate the search to open questions. It's all documented in the help center and IMHO is one of the most powerful tools in the arsenal for site moderation. (I've used it to shut down massive spam rings in the past.)

The list of linked questions is a good place to start; I've already identified more than two dozen likely duplicates. The duplicate close vote review queue is probably even better, since I already voted to close on those likely dupes.