Hey doc.
Pre-delay is the amount of time between the actual sound and when the reverb actually starts. More p/d time means the illusion of a bigger space you are in. Since you are recording a classical piece here (per se.....

) that would suggest a big Cathedral or large concert hall. A long p/d will help keep it that way for the listener. Short p/d times tend to make the instrument sound a bit more "washed out" in the mix because the onset of reverb starts before the note has ended. This effect can help "set back" things that seem a little too present in the mix. Longer p/d times will give the illusion that you are in a very big space, but very close to the instrument. Short times will give the illusion that you are in a big space but far away from the instrument.
Yes! Most good reverbs allow you to adjust the decay and decay characteristics of "multi-bands" within the reverb, at least 2 "bands", sometimes three!. Indeed, it IS a very cool parameter to have, and something missing on many cheaper reverb units. Too bad!!!
High-end Roll-off COULD be post reverb EQ, but can also mean PRE reverb EQ, or, more dampening to the decay. So many parameters can effect the high frequency content of reverbs. Which you choose to turn down in the stuff above say 5KHz is up to the user and the desired effect they want. I have run eq's before and after the reverb to achieve different results in taming the high's. Each has it's own merits. I am not a fan of brashy sounding rooms, so I tend to try to make my reverbs a bit darker sounding. This also tends to "blend" the reverb with the original sound a bit better, making the reverb a bit less obvious while still contributing depth to the mix.
Ed