Grookey -> Tempan -> Kongobongo
Base Stats: Kongobongo - Slow, but bulky and good Attack
Theme: Music (specifically from percussion instruments)
Moves: Leaf Tornado, Uproar, Synchronoise, Boomburst, Rock Slide

Scorbunny -> Rabblitz -> Lagostrike
Base Stats: Lagostrike - Mixed and speedy, but frail
Theme: Sports (mainly running-related like track and soccer)
Moves: Ember, Quick Attack, Flame Charge, Spark, Agility

Sobble -> Watear -> Trageleo
Base Stats: Tragemelo - Balanced with Sp. Atk being the highest
Theme: Theater/Drama and "ghost" writing for Tragemeleo
Moves: Water Gun, Fake Tears, Lick, Acid Armor, Camouflage

Which one?