1. How weird, it absolutely does feel similar in both the fleshiness and the weird energy. It's not exactly the same, but he will be able to tell that it's a very similar location.

2. Sure is!

3. The membrane quivers and shakes in response to any attempt to manipulate it, so it seems like it's slightly more able to be messed with than the cistern walls. Damaging it in any way makes it instantly and visibly heal over with knotty-looking scar tissue. Repeated manipulation attempts do start to make it look more... ragged. Over time.