Some answers off the top of my head that are sure to be corrected by the others...
Lovecraftforever wrote:Who is Sheriff Strand?
You probably mean Sheriff von Zarovich. he's a rather unpopular creation from the rather unpopular book
Champions of Darkness. his background is a mystery, but he's loyal to Strahd and wears an executioner's hood, and is a very over the top blood and gore brute of a villain compared to the more refined Strahd most people are used to, and quite frankly that's all I remember about him other than the near unanimous hatred of him online.
Does Barovia have any other major towns?
Plenty!
see the list here:
http://fraternityofshadows.com/wiki/Barovia
(though it's missing Berez at least, so it needs updating)
What happened to Strands other relatives?
His brother Sturm wasn't at the wedding, but at least some of Sturm's descendents ended up in Ravenloft's Barovia anyway, so there are other Von Zarovich's in Barovia. Notably, Lyssa (from Children of the Night:Vampires, Thoughts of Darkness, and Gaz I) and Talena (from Legacy of the Blood) and a paladin whose name escapes me, also from LotB. (You too can be a von Zarovich with the rules in LotB, BTW!)
What happened to the drow settlements from 2ed?
incorporated into the backstory of the Shadow Rift. Basically, there were only a few drow, the rest of the creatures mistaken for Drow by the general populace were actually shadow fey/Arak. the few Drow outsiders however spread their Lolth worship among some of the shadow fey.
Does Ravenloft have a underdark?
not officially, but there was a spellfire card (or was it a TSR trading card?) called "The Underdread".
Do worshippers of devils and demons maintain any power in Ravenloft?
There are probably some in Children of the Night:Demons, though that's only semi-canon. I can't think of any canon ones offhand, but the "bust up the demon-worshipping cult " is a pretty standard homebrew Ravenloft adventure, it seems.
(There's also Malistroi, a demon (devil? I forget) who impersonated the false god Zhakata, if that counts...)