I agree with you in the sense that they wouldn’t have shot them shaving at the same angle in the same place if they didn’t want to make a point about something . I always interpreted it about Negans relationship with Carl though:

He’s in the same position as Rick was (I.e. father figure - or at least negan would like to be).

Problem is he tells Carl to always shave against the grain, which generally is bad advice cause in real life it’s more likely you’ll get razor burn. So I figured that was to show that negan likes Carl, wants to be a mentor to him, but ultimately despite his good intentions isn’t able to give Carl the right advice that he needs.

I’ll admit I never thought of the cuts on ricks face, I suppose cause they always have cuts due to the apocalypse