I'm no picture assistant, but my understanding of this is that the picture assistant would load the pictures and 8 track poly files into the video editing system in a way that reads the WAV meta data. They then sync the two together and cut the show. If the editor only wants to use one of the eight tracks that's okay.
On completion of edit they export an AAF (OMFs strip meta data) and you load that into PT (I'm assuming your using PT). You then expand tracks on the single track you have in the AAF to create new tracks with the alt channels recorded or just select a different channel from one of the eight original channels/tracks. Well that's a basic overview.
If for some reason the meta data is missing in the AAF when you import into PT you can use something like EdiLoad
to conform your WAVs to match what was edited in the video edit by getting an audio EDL from them.