I'm certain Fisticuff only gives Johnny the fist bump powerup and the infinite string. Red Glow showing up in Stunt Double proves it's across all his variations. Another thing: If Red Glow makes moves ex for free, how come Shadow Kick didn't go full-screen when he was in glow mode when they demo'd Fisticuffs? EX Shadow Kick is supposed to go full screen and have armor, but in the one instance we saw them do a Red Shadow Kick, it didn't go full screen and stopped in front of Raiden.
Since it was brought up earlier, Stunt Double only gives two shadows. The reason why I like this variation more than the other two is because it's similar to Lobo (Sinestro and Green Arrow are similar in this case, as well) and how he has to gain his trait without getting bodied for doing it in neutral. For Lobo to get his two shells, he needs to do a full combo and end with f21 xx trait/21 xx trait. If he uses a shot afterwards then lands a MB grab or any kind of hit, he can easily do this same tactic to load up his second shot and go back to having full shots.
With Johnny Cage, I imagine most combos will go: pop up string, dash up, 114 xx stunt double activation/fisticuff activation to guarantee getting those variations in without getting a projectile to the face or a full screen attack punishing you. Used up a double by throwing a projectile? Land another hit and end in loading up your shadows again. This fixes the "only two shadows?" problem, you are able to replenish your shadows mid-combo.