It's like an Emily Henry version of Seven Husbands of Evelyn Hugo...
I liked it, but honestly, the real MVP here was the narrator. the ending of this story is sad, and it's not exactly a miscommunication trope, but it's the same vibe to me. 
Alice is out Sunshine, and Hayden is our Grumpy and they are the main story. Them competing to writing Margaret's life story is the subplot. How does one write a story when the subject is purposely leaving holes and telling half truths? Alice uncovers secrets and is forced into silence because of an NDA causing issues for her own love story.