Question : Group Policy for FireFox

Is it possible to install Firefox and disable by policy the ability to use add-ons?

Answer : Group Policy for FireFox

As far as I know, Firefox doesn't support Active Directory, but there are som 3rd party tools here:
https://wiki.mozilla.org/Firefox:2.0_Institutional_Deployment

But I think those are for old versions of Firefox, and no longer supported.