The Caretaker is of the Plunderphonics/Hauntology/(most commonly known)Vaporwave genre. The genre is music that has been messed with to sound different. It's a sample, so The Caretaker has the right to his versions of the songs. The Caretaker music is not copyrighted, so, in YouTube videos for example you can use it.
The music in AEwVS has nothing to do with the caretaker because it's the original sample. It's exactly the same as "When Summer is Gone" and copyright, not sure what would the label owners do if they found out, but so far no one cares about the 20's-30's tunes being used. So AEwVS will be fine even if it gets bigger. No copyright problems most likely.