Galaxie,
If the WTBTS is correct then Eve's sin was the first human sin, with Adam following suit. The WTBTS says that since Adam was the " spiritual head" of Eve, he could have said, "NO!!", to the forbidden fruit. Then God could have disintergrated Eve and made Adam a new wife, and things would have went another direction. I assume in that alternate timeline, Satan is destroyed by God. The "universal sovreignty" issue was only an issue because Adam sided with Eve when she tempted him. Adam loved Eve more than God according to the WTBTS. Wow. According to the WTBTS, the fate of man seemed to be in the hands of man. It seems that humans are expected to take on a lot of responsibility...
If the WTBTS is right about Satan turning evil, then his/her/it's "original sin" would be the exact moment of rebellion, whenever that happened to be. So we actually have 2 original sins! One for Satan and one for humans.
Also, I am anti-WTBTS/GB/FDS/Organized religion. There are many individual JWs that I like. What am I? I am just accumulating information. I am an INTJ type who reads about anything from aliens to zoology. I am just what I am.
DD