I've worked the issue out in DM's. To those in the future reading this thread, let me tell you a tale of how .webm isn't supported across all programs. The way .webm is encodes transparency is still a newer use of the format and isn't quite supported across all browsers. It works for Firefox, Chrome, and Edge at the very least, and probably some other browsers, but its support isn't universal. The background issue shown in the above image is a result of artifacts that come about from the transparency not being read correctly. As it turns out, even having the transparent .webm file wasn't enough for me to composite the file onto the figure as requested. Instead, I had to hunt around for a program that could read the transparency properly. My usual program of choice is somehow able to export transparent .webm, but not import it for some weird reason. Eventually, I found that using OBS of all programs, I was able to read the transparent .webm and put a greenscreen underneath it, record the greenscreened animation, and remove the greenscreen in my program of choice to get the image set up properly and exported. The method I described earlier using EZgif will work perfectly fine if you're using a .gif animation and want to put an image over it, but I naively assumed that the built in .webm converter preserved the transparency of the .webm file. It does not. If you're interested in getting a .webm animation you've purchased from the marketplace into it's own unique token, you'll either have to use the method I described here, or try to contact the original author and cross your fingers that they are willing to work with you to make the token work properly. Regardless though, my method only really works for images that are fully opaque and fully transparent. If you had an image that has a fading effect of transparency, this method wouldn't work, and you'd have to do extra effects work after the fact to get that transparency back.
