Sorry for the necro, but the closest I have been able to do is use the lattice tool to transform the scene into an oblique scene and then use a normal orthographic camera. The only problem with this is it flattens out the curved surfaces and that affects shading. I made a video a while back showing how I did this. I do not know how to put audio on video, so it is video only.
Here is my description of what I was doing in the video: https://otland.net/threads/using-blender-to-create-sprites.252078/post-2446705