Howdy.
1. iTunes has no problem handling 24/96 material. However, it does not automatically switch sample rates to match that of the source file. This needs to be done manually when switching sample rates in the AudioMidi utility. Other audio apps (PM/PV, Amarra, etc.), working in tandem with iTunes, enable automatic sample rate switching as required. I cant say if the SB Touch does this as I'm not familiar with it.
2. Again, not being familiar with the SB Touch, I can't say if it works similar to the other playback apps I've mentioned above which only use iTunes as a file management front end. Not sure if PM would be of any benefit in your scenario, or if it's even possible.