In your request to "insert under or wrap children" - you can already easily add multiple divs to any area and make them either children or on same level. If you just keep clicking Add Div, they go in as children and you can adjust using the "move left" button.
Is that what you were looking for?
Best - Joe
missed answering this one
just as an example
you want to insert another 'everythingWrapper' div around 'outerWrapper'
can't see how you would do that as the closing div tag as is always inserted straight
after the opening div
or did I miss something?