For the top of Lovis' Tower do you mean where his skeleton smith is? There are (trapped) buttons on the wall beside each symbol, activate them and you will get a scrying stone (an artifact for the priest, though you may want to use it before bringing it back). The highest door I recall is Lovis' chamber.
Mindread the guy without a tongue, and then check the bookcase on the other side of the room (looting on the way).
The 3 talismans get used in the central area of the cave system where they are found, in front of a well lit statue (near the top of a set of stairs, with one wall of the room metal bars or some kind of grating).