If I decided to buy a ticket, should I get Nike U or Water Raph? Or someone else?

I currently have Sol, Cthulhu, SR Nike, and that's it. Not sure how I'd go about getting Belphegor or Triton as a (up to now) free player. As far as Souls go, I have Mordred and am very close to D'art. I'm level 47 so it's gonna take forever to get Joan D'arc.

Nike's Def A debuff synergyzes well because I currently have Def B and Def C debuffs, but not A. The heal is always great but not crucial since I have Sol.

Snow Raphael's overdrive reduction is always great but not crucial since I have Cthulhu and Mordred. Her 2nd ability seems good but I have no idea what it actually does. It buffs your team's defense for two turns, same as SR Nike? Her first ability is kinda pointless since I'm about to get Sniper Shot. And Mordred herself already has a backup B debuff on her first ability.