the F3 screens will fit a F2 although they have a 'key' the F3 screens are brighter... donno about full inter changibility F, F2, F3 the F3 may need the key to retain or fit...
well a F3 screen and mount will fit in a F2 and should be same at infinity, only swapped F and F2 screens between mounts and Im told F4 screens will swap in to earlier mounts donno myself
The screens are the same, however, if you install an F/F2 screen into an F3 without using the F3 frame, you won't be able to easily remove it. Nikon did that with the F3 Limited. Screen has the F/F2 style frame on it. A repair shop or someone with the correct tools is needed to remove the screen on that version.
Unlike the F and F2 bodies, the F3 doesn't use the same method of holding the screen and finder in place. Instead, it has a lip on the screen frame that is used to lift the screen out. The F4 screens have a different condenser glass piece, so there will be focusing errors if you try to use an F4 screen in an F3 or vice versa.