EOM,
I appreciate what you are saying, but I noticed something immediately about the book of Jasher you quote that contradicts the Bible. In verse 19 it speaks of Abel asking why Cain eats the flesh of his flock. I believe the first mention of the animals being given for food in the Bible was after the flood when God made the Rainbow Covenant with Noah. Since Cain and Abel were the first generation to be born after Adam and Eve falling from perfection, why would he be eating animal flesh before it was given to man to do so? I don't think the book of Jasher is anything other than an interesting apocraphyl book. Sorry to be a nit-picker, but that is why I don't feel these types of writings are very useful beyond their historical perspective of the people of that time.
TYA