Ah, if you did Fix Match in step 6, then there was no reason (I think) to edit the display and sort titles in step 4. If you change which show that it is matched to, all unlocked metadata will update automatically. Having locked them in step 4 will keep them from being updated when you matched in 6. Of course, if you named them well in step 4, then it’s unlikely to be any different. If that’s ok with you, then leave it. I personally don’t like to lock a metadata field unless I have a real good reason for it, and this isn’t one of those reasons to me.
Sorry that there was so much difficulty in getting this show to display. It looks like, now, the reason it wouldn’t show up after renaming the file over and over and over was because it was already matched as a duplicate to another show. Checking my own library, I checked for duplicates and I found some! It seems I had some folders named badly, or some actual duplicates.
For the ones named badly (one season had no “Sxx” prefix, so it matched those episodes as duplicates of season 1), they would NOT get corrected in Plex automatically. They still displayed as duplicates of the wrong episode, despite the name being correct now. And that is due to Plex’s tendency to be sticky. That is, if you match a show or episode, and then change the filename or folders AFTERWARDS, Plex will notice the rename and keep the association between the duplicates. To fix this, you must take the files out of Plex’s visibility (I put it in my media’s root folder), scan the show, then add them back in, and rescan again. This causes Plex to forget the association (first scan with file gone), and then when the file is added back in it’s considered a “new” file and matched up according to the naming rules (second scan). This is essentially the Plex dance, and I forgot that it was an important step.