Single firefox profile across all users and profiles on networks

Question

I'm in the process of setting up Firefox as the standard browser for an entire building, and part of this is ensuring that everyone's firefox profiles are saved to personal network drives as opposed to the local machines. I can use the profile manager to do this on a user-to-user basis, but what if I want all the users of any machine to use the same firefox profile that points to a specific network drive? (This will ensure users always have their browser settings and such regardless of where they access them, allow us to switch machines out without losing anyone's browser settings, etc. The contents of this drive are specific to the user account, but always have the same path.)
As far as I can tell, profiles created in the profile manager are specific to each (domain) user, which would mean an awful lot of manual profile creation. Is there some way to ensure Firefox always uses a specific Firefox profile or path? Is there some way to have firefox check which profiles exist (in a .bat file, for example), so I can create the proper one if needed? Can I use a command line to set which profile to use by default, or can that only be done from the profile manager GUI?
Finally, and this one may warrant a separate query, but I've found that when using profiles that point to a network drive, trying to open firefox on multiple computers will fail (another instance of firefox is open, close it or restart). Can I tell Firefox to force the old instance closed, or will I have to firefox.exe -no-remote -p "differentProfile" every time?
We're on Windows 7, by the way, for references' sake.

Answer 1

We just deploy images, so everyone should have firefox already, but we're pretty good about keeping all data on mapped network drives instead of letting windows save things locally, so I'm trying to find the best way to integrate Firefox in that system as well.
Every user has a network domain account, which can be accessed from anywhere in the building. While mostly people use their own computers, due to the nature of the place, that is often not the case, and several people will need to sign on to the same machine on a given day.
If there are command-line ways of checking for firefox profiles, I can have them run in our logon script to ensure everyone always has access to their personal profiles, but I'm not sure the best way to go about that, yet. I suppose that's the main part of my second question--what is the cleanest way to check for and create/map/assign firefox profiles automatically?