Sorry, we actually use the Adobe suite which is probably out of your price range and it has a learning curve. Not sure about the freeware out there, but face tracking is an aspect of most photo/ video software now. The best bet is probably still adding a layer on top of your video as a screen or a solid object like an oval. Unless you have a lot of movement you won't need to add keyframes every frame or even every second for the motion.
The big issue in many LS groups and communities is getting permission to post the pictures or video of who you are with. Once they are out there they run off and bounce around the web. I found out one day that I was a German Milf on holiday in London... Getting video taken down is next to impossible. But, with others in your videos: We know a few people involved in active suits. Protect yourselves legally as much as possible with a signed "contract" if you are going to publish the video.
