In regards to my question, hbrock at Avid Forum posted this:
Importing files, static images or Quicktimes creates Avid Media. The only way to recreate that Avid Media is to repeat the Import process by using Batch Import as there is no relationship between the source and the media beyond the imported file location. No reel number and no time code means no relinking.
Titles, graphic images with Pan & Zoom moves and rendered effects are alll pre-computes (aka renders). Renders don’t migrate, they need to be recreated if you didn’t move those files to another machine. Generally that’s too much trouble as it’s very hard to determine what pre-computes are used and which ones are no longer necessary, so re-rendering is preferable. Titles need to be re-created by selecting a sequence, setting in and out points and selecting “Re-create Title Media”.
AMA is a more robust alternative to Importing as it uses the metadata of the original source file to create a link to any Avid Media that is created by Consolidating and/or Transcoding. If you brought in your XDCAM sources via AMA (keep those AMA bins!) and didn’t have the Avid Media you could relink to the original source media by doing a relink to AMA sources as long as those clips are online.
Finally, the media database files inside the Avid MediaFiles folder are just a index of how many files the folder should contain (that’s why it re-scans if you add a file to the MediaFiles folder) as well as a what timecode and reel number (or source name) goes with each clip so Media Composer knows what media is online.