It took some effort to figure out some of the scaling issues, but using this method I can import new animations.

Downside: existing animations will no longer work.   I might be able to find a solution once I get my plugin working.
Once I get done adding animations, I can change the bone names to match the Bip pattern and add the tag bones, and any other bones like the tail, or for clothing.

Also the animations get exported all in one skeleton file.

To see it for yourself check out the attached mesh/skeleton in the attached zip with ogremeshy and look at the animations tab.

These are all from the axe pack available for free from mixamo.

I have well over 100 animations I can import. So the start of a playable Ponya could be coming soon.

I did a test into TL1 replacing an NPC, quest icons are hard coded to appear above "Bip Head" so the bones will need renamed for everything to work properly.

Basically, I've used an entirely new skeleton with the old mesh weighted to it. The skeleton's are not compatible.
Now you could use the new setup as an entirely different "model" in the game and it would not affect the current npc model animations. You would just have to treat them separate.

Since I'm starting with skeleton and animations in blender, it makes it so I can edit them and create new ones and export to ogre format.