OSes have to move on at some point and, unfortunately, some software and hardware has to be left behind. The benefits of a newer OS can outweigh the shortcomings though. Still, a few hacks can get them working again or near abouts, usually. :)
Project Dollhouse: The unofficial-official server for The Sims Online. Lol. :D
I can see private servers working well if you just want to play on your own (?) or with your own select group of friends. Other than that a "public" server would be more fun IMO.
Oh my gosh. Looking at all of this must be a big mess. There's nothing worse than unorganised code and code which you think does/references one thing but does/referenced another. Still, you're making great progress and you're flying through this! :)