I think you're right. If the cloak had been at Godric Hollow that night, I'm sure Harry would have bee hidden in it. Who gave the cloak to Harry? If it's dangerous, why give it to some who just found out he was a wizard? If it were a family heirloom why didn't Harry receive all of his heirlooms, like the communication mirror, which was less dangerous? Too many questions, we just have to wait.