A little conversation will reveal that George Ostin, the man who was murdered at the start of the game, was dating Kendra's mom, Lia. She'll also tell you that her dad is Emil, and he works at a place called the "Abacus."
Another thing you should say to Kendra is something I would never say to a girl kid if I was a creepy guy in a fedora and a trench coat, and that's to ask her to come with you. Stranger danger! But do it anyway.
Hint 4
No matter what reason you give, she asks what she should have for breakfast, then goes back to the piano. She's clearly looking for a specific answer, but what?