Find raw footage based on second hand video?
In Premiere, you can align clips based on audio by putting the clips on separate tracks, selecting them both, right-clicking on one, and choosing, "Synchronize."

As far as "programs to compare edits with raw footage," DaVinci Resolve has a pretty robust conform process that lets you play a reference video along with any xml you've got from Premiere (or FCPX, Avid, whatever).  It also has a Scene Cut detection feature, which is helpful when there are a lot of "bits" to extract.  I don't remember which features are included in the free version of Resolve, but BlackMagic typically only restricts features meant for Hollywood studios.  It's worth learning, if you have the chance, just to use whichever tool meets your needs.  

But if you don't have time to dive into another full NLE, you could just stack your reference video at the top of your Premiere timeline, turn the opacity down, and lock the track.