Blender Underground

In pose mode, how do i restart all the bones?
Like get them in the original position.

Also, how do i cut an object into two? (the opposite of ctrl + j)

I know the answer of the second question: In edit-mode, select whatever you want to be separated into another objects and press "P" and choose "selected".

To the first question, well I have no idea.

If you want to clear the posing for one or more bones, select the bones and press ALT+R to clear rotations, ALT+S to clear scaling and ALT+G to clear translations. Issuing these three commands will all bones selected will return the armature to its rest position.