[Tuidjy]

Ibol, both of these happen exactly as Fennrick described. This is how it has always been, and I always assumed that it was intended.

1) All quest monster respawn forever.
2) Boss monsters save as normal monsters, and vice verse - something that was a normal monster can be a boss next time you visit. I guess 'bossness' gets rolled when the map is loaded.

By the way, both of these can be to the player's advantage - if you need a quick relation change, you can visit an old quest sector, and if you cannot handle a boss, you can reload the map.