User blog comment:JKGame/Update on the Heroes Tournament and My Rap Battle Series/@comment-27614603-20190911204903

My guesses for some of them:

MLRB 2-1: Palutena vs. Celestia

MLRB 2-2: Hermione vs. Twilight

MLRB 2-5: Spike vs. ???

MLRB 2-6: Grogar vs. Thanos

MLRB 3-5: Gandalf/Frodo/Legolas

MLRB 3-6: Big Mac (obvious)

FEvH 2: Chrom vs. ???

FEvH 3: Guy Fawkes vs. ???

FEvH 5: Sora vs. ???

FEvH 6: Sacagawea vs. ???

FEvH 7: Marth vs. Erdrick