I purchased this demo tape off of ebay 12 years ago. There was limited information from the seller, other than that he purchased it at a yard sale in Montana. One side of the cassette contains three tracks I cannot identify as Bad Radio Songs. The fourth track is the acoustic version of Homeless. The other side of the cassette contains 4 recognized Bad Radio Songs.
The cassette holder is visible in the video. There is writing in white-out on the cassette, which labels one side "Bad Radio", and the other side "The Butts". A written note inside the cassette says "this is the butts first demo. must see live. keep in touch. eddie (phone #)"
If these three tracks are indeed The Butts and not Bad Radio, then I believe it will be the earliest known recordings from Eddie Vedder.