Update:
It booted! (Sadly, it was a complete MacGyver job. Since I had the image I cloned the drive with, I figured I had nothing to lose, so I replaced the COMPONENTS file with the backup I mentioned, added any missing manifests from my dad's laptop and did one last DISM/SFC cycle, referencing a copy of his WinSxS I made onto an external drive. This caused it to pick up several thousand new corruptions and fix them.)
However...
You'll be pleased to know that once booted back into Windows, I immediately countered this by doing the repair install. Since this could now be done within Windows, I've kept all of my files, apps and settings intact and also finally updated!
Thank you both so much for your help over the past week
It booted! (Sadly, it was a complete MacGyver job. Since I had the image I cloned the drive with, I figured I had nothing to lose, so I replaced the COMPONENTS file with the backup I mentioned, added any missing manifests from my dad's laptop and did one last DISM/SFC cycle, referencing a copy of his WinSxS I made onto an external drive. This caused it to pick up several thousand new corruptions and fix them.)
However...
You'll be pleased to know that once booted back into Windows, I immediately countered this by doing the repair install. Since this could now be done within Windows, I've kept all of my files, apps and settings intact and also finally updated!
Thank you both so much for your help over the past week