They have access to all abilities - which now reminds me I need to put a limit of "one use of the ability at a time" so you don't have 80,000 duplicates running around casting spells for you, if you happen to be a KoT 5/Ur-Priest 10 or some other crazy PrC that grants level 9 spells over 10 levels.
Or, they could just not cast spells above a certain KoT level. Say, they can only cast spells up to spell level (KoT levels - 5) or something. It'd take 14 levels of KoT to gain the ability for duplicates to cast 9th level spells, which would take you way into Epic levels to get that.
Also oops - Limited Time Travel should be a standard. I'll fix that right away!
Welcome to the fanbase! Thanks for the kind words. Though, some of the abilities here are based off of stuff you don't find out till later in the story, so it might be sort of spoilery, sorry about that.