Witchlin Fen I had seen the name before but have absolutely no idea what this zone was-
old Mino Isle all I remember about it was it being bland and having a couple of nice pieces of equipment, end mob might've been named Bul
Caverns of Lloth ended up being remade/re-imagined as Theiwar Caverns. The old zone ended with Lloth the spider queen, only thing I remember of that was the mob breathing acid and fragging the hell out of everything. New zone has some sort of theme around the Theiwar trying to summon Lloth from another dimension or something, but the mob itself doesn't exist anymore.
Celestial having so little time is very odd, I'd guess that might be when it was added to the game? Or possibly was delinked for a time or moved to a new location and hadn't been rediscovered.
I tried searching the news for anything on the Resaina zone but nothing came up, seems to have only been in the game from April '97 to Jan '98 too, maybe had some problems that got noticed and never got fixed.
Some other funny random stuff I passed by in the news that people may remember, laws being introduced to the game. Doing anything aggressive within a town, including stealing from and killing certain mobs would flag you with crimes and make guards attack on sight and yell to the town about your crimes. Some or maybe all would last a decent amount of time also, I want to say one or two game days. I think you could go to a judge in one or some towns, used to be like judge Wapner or some dumb name in Kalaman and pay fines to get rid of your crime flags.
Also diseases being added to the game was pretty funny at first, they spread incredibly easy and would spread from players to mobs just from being in the same room with probably no immunity flags on anything at the time. This lead to someone getting a disease in a zone then recalling, giving it to the innkeeper, shopkeepers, guildmasters, who in turn gave it to every other person that came into town. Every person and mob you ran into would be coughing and sneezing and it was near impossible to get rid of it for more than a few minutes.
For the part of the original post asking about overlords, April 23, 2000 news has the first mention of Aristox stepping in to relieve Cale as overlord. He ran and shaped the game for by far the longest, a bit over sixteen years out of the ~26 that the game has been going. Most of the rest that were the main figurehead probably did it for about a year at a time at most. A few in the couple of years before him were Flint (possibly also as Barkhor?), Goldmoon (maybe also briefly as Carp), Morgion, I think Mahasamarahu came back for like a month at some point