This might be a little long, but there's something confusing me after having just read your Lil' Cal timeline. Lil' Cal is "full" (with souls) when he is with John in the ectobiology lab. This means that exact version of Lil' Cal is both sent back with Bro /and/ sent back with Dirk and grows up with both of them (pre/post-scratch). So why is Bro's Full and Dirk's Empty? Shouldn't they both be Full?
Two copies of a juju can’t exist at the same time. So one retained its juju properties and the other lost them.