making a virtual choir video

You can certainly do it, putting each video on a separate track and then resizing each image and positioning in the video frame, but it's not easy. At least not unless you're good at synching video and audio tracks and using the Scale and Position effects. 

Sorry, no experience.
But we have tried to play Quartte, Violin, Viola, Cello each separatly recordet in relataion with an refernc record.
We edited this 4 recors with ZOOM.
The problem was that withaout a conductor, it dont work well