Odd-Eyed

For Hibiki a Coronamon who digivolves into Apollomon.

For Tsubasa a Veemon who digivolves into UlforceVeedramon.

For Chris a Palmon who digivolves into Rosemon.

For Miku a Renamon who digivolves into Kuzuhamon.

You've missed your opportunity to give Miku a Lunamon who evolves into a Dianamon

Who can then fuse with Hibiki's Apollomon into Gracenovamon

So Kuzuhamon representing Miku having a "shadowy" side, but one she can use to protect Hibiki to serve as a contrast to her being the Sunshine felt better to me.

Also, the Sun and Moon motif felt more like a Kirika and Shirabe thing, but I preferred giving them an Angewomon and LadyDevimon.

Miku quit the track team because she saw Hibiki's kindness and wanted to better herself in response, to walk alongside her instead of running by herself. Her kindness is literally Hibiki's kindness reflected back at Hibiki, it's a kindness loop. Hence why the moon works for her.

For Hibiki a Coronamon who digivolves into Apollomon.

For Tsubasa a Veemon who digivolves into UlforceVeedramon.

For Chris a Palmon who digivolves into Rosemon.

For Miku a Renamon who digivolves into Kuzuhamon.

You've missed your opportunity to give Miku a Lunamon who evolves into a Dianamon

Who can then fuse with Hibiki's Apollomon into Gracenovamon