...click on a hotspot on a panoramic frame, the variable changes, so the object you picked up is disappearing.
Unless there's a way to script it, or to use the Key Guard plug-in, I don't think that you can properly acquire or use Inventory items in a pano room. You can, however, "fake it" by using variables as GM does in his pano demo. So the answer to the first part of your question is "yes".
I would not try to acquire or use "real" inventory items in a pano room, because things can get pretty wonky. For instance --- For a test, I added a key to inventory in a pano room by using the usual check boxes in the hotspot properties box. The good news is that when I picked up the key, the inventory bar dropped down for a few seconds, and when I then moved via hotspot to a non-pano room, the key was available in my inventory. The bad news is, the inactive hotspot remained visible, though it did become inactive. I tried using both the inventory and hiding the hotspot after it's clicked with a variable as well with the same results. So, nada to the inventory items.
As for the rest of your questions, I don't know. Sorry. Had the quality of the panoramas been better, I was planning to use them mostly as nodes for viewing the surroundings, then do all of the actual inventory, puzzle work, etc. in still frames.
For instance --- You enter a (pano room) library, which can exit via a hotspot to the adjacent (pano room) hallway. Inside the library there are items on a (hotspot) desk that, when clicked, give a (still frame) close-up of the items on the desk, which can be acquired into inventory or used there. I think that could work.
Now I have problems with panoramic pictures. I tried to find a program which is suitable for this work, and I decided to get Vue 5. I really like the problem, but I was really disappointed when the panoramic pictures I made didn't fit on the cylinder of AM... I read the help file of Vue, and if I didn't miss anything, then it said I created cylindrical panoramic pictures (there are another option which I could use to make spherical ones, but of course that didn't fit too... 
) So my problem is this. i can't understand what's the matter: I tried to use the original resolutions (800*600 and things like that) and the resolution given in the example game (2048*2048 I guess) but none of them worked. The problem is with the sky and the ground: at those points you can see that you are in a cylinder. And the whole image is not realistic (not due to the lack of my modelling abilities... ): the straight lines are curved and things like that. So it doesn't work. Anybody who knows whats the problem and whats the solution? If it's possible, I don't want to work with another software...
