2D/3D Animation

I need to put faces, that have already been recorded on green screen, onto the bodies of water contaminants like chlorine, e-coli, etc. These contaminants need to look like contaminants, they can be animated, cartoonish, doesn't matter, they just need to be undeniably noticeable as contaminants. The trick here would be the grab the footage that I have already recorded on green screen 4K proress, and place that on the bodies of the contaminants. In these clips, all the contaminants will be floating around inside of a liver (liver must be noticeable in the background). On a couple of clips, a contaminant will have a piece of dialogue to deliver. So there will be audio. Again, it has been recorded already. Deliverables: 3X 10-12sec animated clips