Chaos rings omega extra mode and other scenarios?

in extra mode theres an option to partner up with either dante or vahti, so which one is better? I wanna pick dante cause I can just go to the main storyline and play as vieg and vahti. but on the other hand I dont want to really play as dante. Or is there an option to switch between them throughout the extra mode. and if not which one should i pick. and also, is there gonna be anymore scenarios. I wanna see yorath and cyllis' story! that be really cool :)