In Madden 19 you absolutely COULD edit real NFL player's faces. I have replaced countless real NFL players' faces with generic ones because they looked closer. Like Arik Armstead. They have him so utterly wrong, so I replaced him with the closest looking generic face. Did the same with CJ Beathard until they fixed it for '19, and I also did it for Nick Mullens.
So don't even start with "you can't edit real NFL players faces because teh NFLPA" crap. That's not why. That's not it. Not at all.
And yes, the problem is you can't use the editor outside of the FoTF mode.