About the James issue... you're actually very right, and it's something I hadn't thought about really (that it wouldn't have really stuck out, if people hadn't commented on it both in the book and in fandom.) And even now it doesn't strike me as particularly noteworthy - Snape does it too, you know? So yes, no disagreements here.

I think sometimes Rowling's intentions are not as clearly carried out as she... intends.