When you're exporting playlists in this case, first, you want to make sure the 'Store paths relative to exported playlist location' is checked. It's also probably best if you store it as an MPL playlist. When you're exporting the playlist, make sure the playlist.mpl is saved in the first shared folder. So, if the USB drives shows up on the Id in /mnt/music, make sure the playlist is saved in the music folder. That should make sure the file locations are translated.
As for the MC23 Linux build, you actually cannot install that on the Id as it is. The Id is an entire system, not just Media Center. To install Media Center 23 for Linux, you would need to install Debian Linux on the machine and then install Media Center 23 for Linux. Information for that would be on the Media Center 22/23 Linux forum; however, I strongly advise against doing this on the Id because recovering the Id would be very difficult, especially if the partitions were changed. The other thing is, we backport a lot of the important Media Center 23 Linux changes to the Id.