So preferably the base of the tail will be hollow, but sturdy, and I'll mount the mechanism to that, running the line through the hollow but maybe with a couple more eyelets for corners. If I rig the wires to my shoulders, so I have to bend over more to pull them, will I need a couple eyelets on my back to help keep it from catching friction on my back? Or should I not be too concerned with that? I suppose I could run straps down to the lines.

The "sock" that will go overtop the mechanism; best to cut out a piece of fabric into a cone shape, do detail and latex coating, then sew together and slide ontop? Or sew it onto the mechanism at a few points?

Not sure I can answer you question about the lines running to your shoulders, having some trouble envisioning it.

I would make the sock/sleeve and then cover the mech. Then I would add details and latex to that. Might be hard to sew once you get details and latex on. I don't think you have to do it in sections. You might want to attach it though to more then one point.

Looks pretty good.

Yeah it's moving well. My only thought is how you  operate it from within the suit.

At the base of the tail where it connects to me, will be the last of the guides for the wires. I'll run the rest to or over my shoulders. When I lean, turn or bend, the tail will move in accordance. That's what I've seen on the videos I based it on. And simply holding it to myself and trying proved to work. It'd be great if I can find a way to pull more of the slack than my body can but I'll settle for what I've got so far.