I'd like to have the ability to merge the cartooning or other Cartoon animator content to merge with real film.   I understand the program would have to interpret the camera differently because it's 2D. So I'm thinking the imported camera's keyframes and lens settings change the rotations and perspective angles of the Character and background...

This might need support for adding a few backgrounds as perspectives of left, right up & down etc or apply cubemapping for full 360 sky rotation. 360 Sky could be a blend of daylight on one side and night on another or perhaps include a Cubemap converter so it becomes a panorama that can be panned and looped with the solved camera.