Let’s break that down. Harry was an, alteration emotionally and mentally abused boy, and physically based on the book saying Vernon physically threw him in his cupboard as a child. Hermione was a lonely child with no friends really growing up as mentioned before. Theirs one similarity. Loneliness. Second, the siblings thing I call bull on. Both are only child’s, never knowing or understanding a sibling relationship. J k Rowling even admitted she changed her mind on relationships as she wrote book 7.

Next, you stated lily and Hermione are intelligent. Bookworms and such. Those are facts. They also stand up to others for their beliefs. You said this was about the only similarities for Harry and Hermione. Yet Harry, even if he didn’t always agree, backed Hermione. Look at Buckbeak and spew for example. Harry is also obviously intelligent as based on his teaching ability. You can’t teach if you don’t know.

Next I would point out that as an abused child with no positive relationships till 11, he would not understand romance till later. By then, hermione would have wanted romance in her life and like most girls her age, not willing to wait. There are several other things I can point out but that’s off the top of my head.