Eiinar,

1. Regarding the tavern: You can always open any original map in the game files and copy the list of available heroes in the tavern from there, and then paste this list into your map file .

2. I'm not sure if it's possible to remove the Thieves' Guild from the town tavern. At least, I haven't encountered anything like that.

3. You can, AllowPlayerTavernRace (for bots and the player) and AllowHeroHiringByRaceForAI (only for bots) will help you).

4. You can, but again, you will probably have to manipulate the race ban for the tavern, because by default the tavern generates heroes randomly. I have a mod that allows all heroes to be available for all maps, and sometimes it's very surprising to start as, say, Knights and have Godric and Biara in the tavern.

5. Hmm... Well, the first thing that comes to mind: take away the cities and heroes from player 2, remove the heroes from the reserve (if any), and then the player, having neither heroes nor cities, will automatically lose. To make a specific player win, you can "dispossess" all the "non-winning" players of their cities and heroes at once.