Here is a song from Slugs and Bugs that will help children memorize Micah 6:8.
Here is a lovely setting of the Micah 6 passage to music: “Offertory” by John Ness Beck. It might be useful as background music for a prayer/contemplative part of a lesson (probably not a song the kids would want to sing). I found it described in more detail at https://artandtheology.org/tag/micah-prophet/.