If you are so keen on extra fights you can always spawn mosnters with the CLUAConsole
code:
CLUAConsole:CreateCreature("creaturecode")[/QUOTE]You can also use that to spawn quest-essential creatures/persons that won't appear (but be sure they aren't just hidden somewhere or you'll end up with two copies of them 
). To get the proper creature code I suggest using one of the creature-lists online or even better Shadowkeepers creature-browser.
The cloning seems to be a ToB issue. I can't remember it occuring in plain SoA. I always thought it was a counter-cheese to the classic "lure monster to other area to finish them one-by-one or just by setting traps". I found that quite annoying sometimes (happened to me once with the entire Guarded compound party) and it's unfair sometimes: e.g. I was to assassinate Rayic Gethras but had no weapons in my party (Viconia and Me) which could hit Stone Golems. So my Assassin scouted ahead hidden in shadows, saw the Golems, laid traps downstairs, went back up and lured them down but regardless how often I killed them they always respawned.