Remove ALL photos and videos from Mac and start again.
Our photos and videos are a massive mess of almost a TB, spread randomly across two MBPs and two external drives, caused by hurriedly and badly backing up many times in different places, general lack of organisation and a total lack of knowing what we're doing. I have several iPhoto, Aperture and now Photos libraries, as well as iMovie projects, photos and videos in many different formats and duplicates galore. I have cleaned the duplicates within each location (the two Macs and the two drives), but there are going to be many thousands between these locations (that's the nature of backups I guess!) whenever I can finally consolidate them all.
The problem is that the mess is too big to put anything together in one place and we're completely overwhelmed; what I'm thinking of doing is getting one enormous external drive, finding all of the files in Finder, saving them to the drive, removing them from the computers altogether and starting again by putting them all in one place - Aperture on the bigger MBP. This will allow me to sort out duplicates, add geotags and generally clean up before importing everything to Photos.
Two questions: 1. Is this a good idea? 2. How do I find all of these files on my MBP? I have so many different formats - most in (now migrated) Photos libraries and many others just in folders (I was going to search by file extension for the latter).
MacBook Pro (15-inch Early 2011), Mac OS X (10.7.5)