There are many relationships in Miss Peregrine's Home for Peculiar Children, Hollow City and Library of Souls by Ransom Riggs.

I have selected all the Peculiar Children and added their relationships with others:

Emma Bloom - Abe Portman, Jacob Portman

Jacob Portman - Emma Bloom

Miss Peregrine - All her peculiar children

Hugh - Fiona

Fiona - Hugh

Millard - He's lonely . . . (tear tumbles down cheek

Horace - He's lonely . . . (tear tumbles down cheek)

Of course, the twins share a special bond. We don't even need to mention that. It's too obvious.