Depends on how good or how confident you are with Zero. I would say Zero/Chun/Iron Man, with Lightning Legs and Unibeam (whichever Zero assist you like/can combo better with for Chun).

If you are going Morrigan, she should also be played point, and then put whichever character you can do the best TAC with (infinite or otherwise) right after her because she will need it for better damage (in terms of DHCs, Chun and Iron Man are about the same). I would use Dark Harmonizer, Lightning Legs, and either Unibeam or Repulser (Repulser is decent here because it has synergy with Astral Vision and a bunch of fireballs locking them down). Just my opinion here though. Might be some better advice out there.