What do you mean by one of the battles? What do you mean by the battles that could be added?
Like the extra people sitting around.
Take the blue exceed for instance.
Carla was used for Wendy's dragon force in tartaros and also Carla's fake death in the Dimaria for the sky girls to fight. Lector was used against Sting in Gmg. Fro's death triggers the shadows to take over Rogue. Pantherlily has never been used for Gajeel but Pantherlily was always portrayed as more of an adult warrior with an exceed form..... who Gajeel partners with as oppose to the other exceeds basically being raised by the dragon slayers.
Plus isn't Happy like 4th favorite character or something from one of the Japanese character polls a few years ago... we don't take notice of him cuz he's literally did nothing this arc.
Which is why I think it's more likely he will be the one killed.....
Cuz he's done nothing this arc except grab Natsu away from Zeref.
Plus Happy early this arc said he would do anything to protect Natsu. Foreshadowing he might try to grab END's book or maybe jump in front of a death blow for Natsu?