Female protagonist is an optional part of P3P, you can still play as "Minato" in P3P even though the non-Tartarus gameplay is in VN-style and the storyline is just identical to "The Journey" from FES.
While Marie's social link is entirely optional, it ties heavily into the main plot and all her introductory scenes are MANDATORY. She is directly tied into the skill cards mechanic. You can not in any way choose to play an original P4 experience in P4G, she is always there.