The hands uncocking would be release. It is an unloading of the barrel. It would be a reaction to the load.
Lag would be barrel still loaded... not being loaded.
This all can be found and learned with the Ryan Braun drill.
He speaks of his bat path, his attack angles. At the same time his hands are articulating the handle to release points to create a short to long through path.
So what is the barrel being loaded with and how is that being released? As I stated in my previous post, the bat is inanimate and incapable of storing energy. So what is being "loaded" and how is it being "unloaded". Is the barrel where these so called "magic beans" are stored that you keep talking about? (Sorry, couldn't resist...)
Note: I agree the hands go through various articulations throughout the swing, but most of them are simply pass through positions that happen naturally as a result of good mechanics. Also, I like the Braun drill and use it often. But probably for different reasons then you. I find it to be a great way to focus on "short to/long through" or swinging "out from" as some would call it.