Yes, that's why I don't like to take Rickman as my basis for Snape. Firstly, he is too funny to be really IC as book!Snape, and secondly, he cannot do a really frightening scowl. :D So I understand how his portrayal of Snape can make him seem more inclined towards children. OTOH, I happen to think as well that Luna would wear anyone down, even book!Snape. :D
Thank you for writing this, I enjoyed reading and imagining the backstory behind it. :D