2 books with so many similarities

Rules for Hearts - Sara Ryan
Sweethearts - Sara Zarr

OK - SO many strange coincidences between these two books that I somehow started reading at the same time.

1) Both have HEARTS in their names
2) Both have authors name Sara (and neither have an H)
3) Both have long lost boys who've been "found"
4) Both have female main characters with things in their pasts they haven't shared with many (or even any) people
5) Both the boys disappear for periods of time in the novel and no one knows where they are adding a layer of mystery to the present in addition to the past.

Both of these books are a bit heavy, not typical "pink" books, surely, but both are very well done and were interesting stories. The stories, incidentally, go in very different directions despite their similarities. I just found the coincidences so interesting, especially since I was reading both at the same time.