During the first mission on halo 1 anniversary, if you look at the computer it says john 117 and next to him Linda 058. does the second character in coop play as her?
No. If you read the books Linda was suppose to go with MC but was injured so only MC made it to the Autumn.
Linda 058 was gravely injured on reach if I recall correctly and was put on cryosleep in order to keep her alive, and her cryo-pod was ejected before the autumn crashed on halo