Replace Footage Premier 15.4. How to replace several at a time

I find that when I think something is overly difficult in Premiere, that there's usually already a better way available.  And there is in this case.  

If you select all the relevant clips in the bin and unlink them and then relink them to the replacement, if the replacement clips have the exact same file names as the original clips, but live in a different folder on your media drive, you should be good to go...   If your bin structure makes selecting all the clips in question timeconsuming, you can just rename the containing folders on your media drive (when Premiere is not running) and when you relaunch your project, Premiere will tell you media is offline and you can then relink to the missing media.  If the folder structure for the replacement media matches the folder structure of the original media, I don't think you'll even have to do the relink dance... 

I do this all the time if I find performance suffers too much because of the codec of the camera original and decide to transcode to a more edit friendly format.  And you don't need to worry about the file extension matching as long as the file name (before the .mov or .mp4 or whatever) matches the original media.

Never really plumbed the depths of the "replace clip" command and how it differs from unlink and relink, but it may work the same way.