Here's what I need to do.

I have a footage of a street. I want to add several people walking. Each person was shot using croma.

I understand how to remove the green using nodes. I understand how to composite each element using nodes. What I don't understand is how could I maniupalte them in 3D space in order to move them where I want each element to be or animate them.

I could use the video as texture on a plane and move the plane around. But I want to know if I can process that video as texture using masks and keying. Or should I key every person, render them, then add them as texture to the planes and work like that?

Thank you