Get it over with - this sounds natural, when you need to get something done. "Get it over" is what we would say if you were playing a volley-ball game, where you must get the ball over the net.

Get sth over with is a phrasal verb. It means = to do or finish an unpleasant but necessary piece of work or duty so that you do not have to worry about it in the future The WHAT is got over with comes between the phrase = get WHAT over with. "You might as well get it over with." = where "it" is the WHAT For example: "We might as well get these homeworks over with."

I surely see your point. Out of context, it helps us know that it is an activity that will happen rather than an object that needs to be raised above another object. In context it will be less necessary. Yet we would expect to hear it anyway. The answer is yes, in context int is only their because we expect to hear it.

Nope, it is not redundant. The verb is: "get it over with"

:P hahaha..good question