I just rendered a test image in maya.
It took a couple hours to get it the way I wanted it, but now that I've relearned how to do this sort of stuff it won't take nearly so long for the actual project.
What I want to do is render a spotlight in maya to follow the dancer, and I'll do a 3d mockup of the topiaries to cast shadows on them. For the dancer's shadow I want to film her with a two camera setup, one to act as the 'spotlight' and one to be the main capture. The spotlight will be stationary way up above her. It doesn't have to be super high resolution since I'm just going to use it to key out the bg and use the dancer for a shadow. I'll put it on a plane in maya and set it to cast shadows but be invisible when it renders.
This is going to be so technically complicated but it's worth the effort.