Superstar
Smash Champion
I don't know about this too much. At the very least, I'm capable of playing SSB64/Guilty Gear and TF2 without any damages to the other. They are very different, but not conflicting different. Although learning FPSs from a fighter is difficult at first. Aim was never my best talent, so much work on that. XDRefer to my above statement. Fighters and FPS's are polar opposites. In fact, they couldn't be any more different.
Playing SSB64 and Melee damages the other slightly, and playing Brawl HURTS my Melee/64. But playing TF2 does nothing.