I ended up bypassing monogames loader and directly load thru assimp to my own model class. Other people have done the same.
Id look up Nkasts aether extras he put in a lot of time on his model stuff and i think he is still working on it from time to time. https://github.com/tainicom/Aether.Extras/tree/2fbb8bb6dfaf35c761ca9f1008018ea097739f43
searching for modeling you should get a huge list of posts. http://community.monogame.net/search?q=skinned%20example
One day eventually ill pick up my own model loader again and refine it. Mine typically loads the maya fbx but with bad scaling and the assimp nuget stuck in it is like a year old.
Still there is tons of notes.
my own git hub project which is collecting dust