What classes get strongholds? Any for a Cavalier by chance?

You get to join the Order of the Radiant Heart, and you get a private room. No place to store gear in it though, and DO NOT leave anything on the ground in there, I lost some important quest items doing that and had to use shadowkeeper to get them back.

Rangers get Merella's cabin in Umar Hills/Imnesvale.

...shadowkeeper? Uh, what is this?

ShadowKeeper is the best BGII editor out there (in my opinion at least).

You can download it in our Editors subsection at http://www.sorcerers.net/Games/BG2/index_editors.htm