So if I put the first person arms animator on the arms, it has no reference to any of the bones, and simply will not work. If I put the first person character controller animator on the arms, (as you do in the FPS mesh video) the arms appear to function correctly. But Andrew and I noticed that with this configuration the arms bounce around way too much any time a new direction is pressed.
For example from sitting still, if I tap WSAD it's like it's snapping to a location each time to start the animation which advisably causes too much movement. This is especially obvious when using the AIM function (holding right mouse) you can see the gun bouncing all around.
This issue doesn't happen in the demo scene so the only conclusion Andrew and I could come to after our meeting was that it had to be the fact that the arms were using the character animator so reacting differently than the FPS arms animator would.
Andrew suggested at the end of our meeting that perhaps the arms animator should be added to the model before separating the arms, that way they could potentially find their bones correct. I attempted this to no avail.
That's all the information I have so far. Andrew has an example scene that properly demonstrates the issue, I can give you a link to that privately if you need Justin.
As for what you said above that sort of makes sense to me, but I'm not sure how to apply that information, if you have a route I could go to experiment further I will try it.
Thank you for your time Andrew, and Justin,
-Seth