I think that Mary Jane and Gwen Stacy should both be in the scene because it would make a whole lot since. Bringing Gwen Stacy back to life would make everything dramatic. Peter Parker would be confused and will be wondering what is going on, will Peter tell Gwen that he is dating Mary Jane or would he try to hide the secret. But the question is how did Gwen come back to life, who brought her back, why did that person bring her back to life. Peter will be in a huge struggle. It just make since guys.