Hey there Betadwarf,
Just bought and tried Multy-Take today, it seams to work to some degree. It does display the separated tracks with the right names in the Sketchfab editor window. But it seams wonky when it comes to the timings of my animations. It leave still frames before the animations starts and doesn't seam to cut off right. Did you ever get a chance to try it out and have it working? Just as an FYI, I did bring the FBX in Unity just to make sure it was good, and it seams to respect the naming of the timing of the animation tracks.
Here is an example of what it outputs
Not everyone can afford a 2000 something dollar program just to export animation tracks... I really hope there is a way to make this plugging work!