Aha, you wanna batch process audio files?
1. Yes. In the audio bin, select all desired files and choose the local menu:
[b]Audio File > Copy/convert file(s)[/b]
In the resulting window you can specify the sample rate you'd like the files to be changed to. You can also specify a name change too.
2. I'm not sure about this one. Try using the above method with files that have the same name but are numbered, e.g. Guitar 1, Guitar 2 etc.
3. I don't think so. When Logic becomes scriptable that might make it possible. In the meantime, check out Sound Track Pro as a possibility to batch apply effects.
In fact, what I'd do in Logic if I wanted to add the same reverb/effect to lots of small audio files:
1. import the audio in the Audio Bin.
2. Drag them all onto the same track in the Arrange, but leave some space between each region.
3. Apply the effect on the insert of the channel strip.
4. Set the End project anchor and choose:
File > Export or File > Bounce...
5. Re-import the resulting audio file, cut it between each audio file and select each region.
6. Ctrl-click on the selected regions and choose: Convert to new audio files (Option - CMD - F).