Mon-El vs Beta Ray Bill
I think Bill wins this on skillNova Prime (Richard Rider with World Mind) vs. Guy Gardener
Nova wins...he's much smarter
Nova Prime without World mind vs Guy Gardener
I think this is close...before he was shown as so clearly below Surfer, I would have picked Nova, now, I'm not sure...in a straightforward way, Guy can actually be very effective, and this time Nova won't really outwit him.
Supergirl vs Zarda
Zarda has a few good showings, but really isn't in the right class...she is a Wonder Woman analog, but is more in the vein of the TV or Superfriends Wonder Woman IMO, not the one who is almost in the truly big leagues. I think Zarda would be a good fight for Valkyrie or Sif, but is completely outclassed here.
MoonKnight vs. Night
MK is significantly more powerful, NW is smarter and a better tactician, I favor MK
Depends whicj Mon though, as the one who was Legion leader very skilled/expereinced, and mor epowerful