I am currently trying to figure out how we can superimpose a us army uniform onto someone via a live feed from a person standing in front of a green screen.

So in detail we are a marketing groups for the us army and as a marketing plan, we want to go to high schools and let students see what they look like in uniform and give them the option to download it from our site. We want them to stand in front of a properly lit green screen with a tv display in front of them allowing them to choose a background to be superimposed into.
After that, have them stand still and get a uniform superimposed onto them. Snap the pic, or grab the screenshot and presto, job complete. They can go online later in the day to download their picture.

But here lies the question. What programs/equipment do I need for this? I want to be able to edit the live feed of what she is seeing on the display in real time from a laptop. Plus I obviously need it to be high resolution.

Any suggestions on a high end, live feed capable, camera?
Programs that allow me to edit a live feed with chroma key(green screen)?
Program that superimposes, or allows me to superimpose, clothing onto someone?