well even after you drop your footage from the CF cards to an EXT Hard Drive you should still be able to playback the clips using XF Utility from the EXT HD. I’ve done this many times. Actually I never watch the clips from the CF card I watch them in XF Utility after I’ve dumped them to an EXT HD. gain, I’ve never had any audio issues.
If you want to take those files and convert them to something to send to someone else then Yes you’ll need edit software like FCP or Avid or Premiere. You might also be able to convert them using VLC or QT Pro.