I missed the news on Reallusion’s excellent Cartoon Animator 4.5, which had an update in July.
Version 4.5 supports export of transparent-background video (.MOV as ProRes 4444) and alpha-masked image sequence (.PNG, lossless, cropped to visible pixels). This means you can just layer the exported animation over your existing video footage, and it should blend in nicely. No green-screening needed, no ugly fringing of pixels at the edges. There’s a new video tutorial on YouTube…