Status Updates From Heartwood

I just noticed that the 3 MCs are completely different perspectives: 1st person present, epistolary (1st person past), and 3rd person present. Why?? And to finally get some insight into what happened to Valerie, I can't help but be frustrated with her, even as I want to murder the person that got her lost. Otherwise, you can clearly see the trajectory of the heart of the story, with the mother-daughter relationships.