Yes, go ahead and edit them as they come up (or edit the backlog slowly)
I previously said that we would rename homebrew to homebrew-review and then retag all the appropriate questions back to homebrew.
We had several reasons to sit on this and wait. One was that at least some of the mods had concerns about how the tags were currently defined. I certainly did. I combed through the list multiple times and each time ended up with a big pile of questions that were ambiguous as to which tag should be applied. So we waited a bit to see how the tag definitions worked out for the current stack before taking any action. For the questions we commonly get here they seem to be working well.
The other issue we had reservations about was that retagging all the homebrew questions to homebrew-review created a situation where the questions had to be manually fixed and preferably sooner rather than later (because, in my mind at least, having regular homebrewing questions under homebrew-review is more wrong and confusing than having review questions under the general homebrew tag).
And for those reasons and others (one certainly being that it wasn't super pressing as an issue), we haven't moved forward as we originally planned to.
Best way forward: retag manually
I agree with linksassin in that we should just retag the questions from homebrew to homebrew-review manually. There's a bunch of them, so it'll take a while but since it isn't a huge issue to have review questions temporarily under the general tag, there's no reason to rush it.
That being said, our usual guidelines apply here when it comes to making minor edits to old posts. Don't flood the recently active page with a bunch of tag edits. Do them in small batches over time. If one of the questions resurfaces naturally obviously, make edits as you normally would.