I think the main difference between the F and F1 is that the F has it's tilt/swing calculator on the side of the rear standard bearer, so that you have to tilt your head to see it, while the F1 has a rotating drum type scale that you can see more easily from the back of the camera.
The F2 has that plus micrometer focus on the front standard, I believe, while the F and F1 do not. I think the F2 standard may also be a bit more robust. The F and F1 front standard can be overtightened easily and broken. It's also easy enough not to overtighten it, if you don't handle the camera like a gorilla.
It is possible to mix and match F and P parts so you can have cameras with various combinations of front and rear standards. A camera with a P rear standard and F front standard is a C. The P has asymmetric tilts and swings instead of a calculator, so if you have a C, you can use the asymmetric tilt/swing feature on the rear standard to determine the best angle for the plane of focus, then transfer the tilt/swing to the front standard using the protractor scales, and zero the rear standard so you don't get the distortion associated with rear movements.
