I started this project with this exact idea in mind, but was met with harsh reality, that WebGL builds cannot record video, or audio without ridiculous hacks (plugins that record video, execute scripts in browser to record html element of game view with browser api). So whole feature was dumbed down. Its also the reason that audio is not positional, since i cannot record it and playback at exact same location.
And yes, all of the animations are from mixamo, some used as-is, some was blended in some way, but in total, there are 60 animations from there.