I'm trying to do a LASO campaign but I can't select any skulls on the menu. So far I picked up 3, but do I have to beat the whole mission with the skull (while holding it) to be able to select it? Please help.
Yes, Halo 2 isn't like Master Chief Collection or Halo 3/ODST and up - Halo 2, you have to play through the entire mission for the skull you want and pick it up to activate the skull AFAIK.