Yes, the Logic 101 - Core Logic 9 covers the Apple Loops Utility:
Check out video 71 onwards...
You simply need to find the the loop on your HD in the Finder and delete it. Is that what you mean?
What do you mean by batch importing? Are the "audio files" already in apple loop format? Or are they regular wave of aiff files? If they're 3rd party apple loops then simply drag the folder that contains them on top of the Loop Browser in Logic.
Adjust key of Loop: Yes, in the Region Parameters box (in the Inspector) you can transpose the loop as long key information was saved when the loop was created.
Hope this helps