First: the heavy pelican that brings in the buildings. These version exist only long time after the sprite of fire has gone missing. This means that the story will partly happen during halo 4/5 and after
second: At least one spartan of red team will survie the story to return the UNSCDF to upgrade on gen 2 armour as we can see throgh the ground pound and thrusters.
Thrid: there are 6 characters to select from with 4 locked, like in Halo Wars 1, i cant tell who the banished leaders will be, but we will get on UNSC side defintly anderson and hopefully not palmer