Getting Started
Maya requires a development kit to be downloaded. Due to certain outside restrictions I have to remain on Maya 2016 SP6, but they no longer have the development kit available on their usual channels... So I'm using a Maya 2016 SP1 devkit from their GitHub! Hopefully there weren't any important devkit changes between SP1 and SP6.
Maya 2016 also requires Visual Studio 2012 Update 4.
Writing the Plug-in
After looking through the documentation, it seems the best plan of action is to write a command for Maya that will perform the skeleton generation. I had originally thought that I would be needing a GUI, but that seems to something that scripting would be more useful for. I suppose that I could combine both scripts and plugins then!
Now just to put algorithms into code...