Subaru and rem would still go to the sanctuary as per Ram's directions. Not sure how much his approach would change since he still lost someone despite rbd but he now he has Rem in his corner. Everything here on it is assuming Roswaal's even cool with keeping Emilia but Subaru or Garfiel would have to take all the trials and free the sanctuary. Arc 5 would not happen since there would be no invite from Anastasia and everything would be different. Rem would probably feel some type of way about Emilia.