1) Mig-21 are VERY DIFFERENT from Su-17/22, the fundamental difference in both is: Su-17/22 is a fighter bomber, and Mig-21 is actually a fighter, with limited capacity for air to ground role. The conception of both aircrafts is very different. this "cross-reference/commonality with the MiG-21" is in practice just for OPERATIONAL purposes, and not for design and research in each aircraft.
2)Lets do a fighter? Seriously? get Mig-21, is a fighter, and, beside F-86, is a multirole, can carry bombs, rockets, guns, anti radiation missiles and of course, nukes.
3) Yes yes, let's do F-4 Phantom, because why? just say "I don't like the Russian made things" and open a poll for the western F-4 Phantom.