1.
The pixi.js renderer on the github repository was the most helpful in making the renderer work. As far as I understand it is as long as you choose the json export you can load it with this plugin.
2.
The way it works is the animations need to be loaded and then it's a simple matter of setting the animation. When I get around to it it can be made to load all the animations from a file and then the current animation, speed of animation and position in the animation can be changed.
3.
"CreatureMeshBone.js" is the meat of the plugin, which made it fairly easy to get working. It does have a feature to blend from one animation to another and you can specify the blend factor from 0 to 1, where 0 is the first animation and 1 would be the second. Any value in between like 0.5 would be a blend of the two. When I get around to it I can implement it, but it would be nice to have an example with more than one animation to test.
4.
It is, I just forgot to uncomment a line in the code. Not sure if the result is very pleasing to the eye.
The loading jank is kind of unavoidable, not sure if I can make it asynchronous, but it would be an idea to explore.