can logic find the tempo of samples?

Insert the BPM counter plug-in on the audio track & it will analyze the file as it plays in real-time, then show the BPM (tempo). I think this plug needs some tweaks or improvements with it's accuracy though, sometimes it's hit or miss depending on if the audio file it's analyzing has enough rhythmic content to base the correct tempo.

It´s in the manual but nonetheless, this is how I do it:

select the region you´re interested in, open it in the sample editor. make sure you adjust the start and end so that it plays smoothly looped.

close the sample editor, select the newly adjusted region. if it is four bars, select four bars in the time line. press Command + T (or go to Options -> Tempo -> Ajust tempo using length and locators)

Presto! The tempo changes, which you can see in the transport. if it says 108.001 it is safe to assume that the tempo is 108. In this case I simply undo til everything is back to where I started. then I change the tempo to 108. done.

In your case it might be more convoluted, considering that you might have chopped up pieces of audio. but the procedure is basically the same, I´d say.

Good luck!
Juhani