But (further to Gen 3:16) if they were created with this Knowledge of Good and Evil, would they not be inclined to sin? More to the point, was the Original Sin inevitable?

Precisely—even more than children are. Children are led to sin through temptation, deception, and curiosity. Adults are led to sin through many more varied and sophisticated means that trade on their experience with the “good and evil” that the world offers. So adults are capable of far greater moral evil than innocent children. Now, whether this means the Original Sin was inevitable is a deep question for philosophy and theology—butit seems to me to be so. It is not even paradoxical to say God created man knowing he would sin, expected it, and prepared for it. Free will plus imperfection equals sin, I would argue. God gave man the opportunity to try to live without sinning, with the very simplest of rules; and he also prepared for redemption and a second creation with those who, despite their sin, could live in him as Adam and Eve once did.