So far, so good. However, one of canon HP's characteristics has been a Hufflepuffish loyalty to his friends. The cold manner he has treated Remus, Sirius, HG and RW with is at stark odds with that part of HP's personality.
I am glad however, that he is reaching out to NL, a character I think too many writers (including JKR) have neglected.
Olaf or whoever he is is right about a couple of issues. First, there have been a few mechanical errors--missing words and so forth. Second, character names do need to be consistent, or, if changed, done so with some explanation.
The rather stilted speech of the nobility is not so troubling to me as to Olaf. The aristocracy of the Wiz World is pretty inbred, smarmy, smug, and self-righteous. It seems logical that they would try to wrap themselves in titles and elegance as much as they could so that they could more thoroughly lord it over the rest of the world--at least in their own minds.
Also, HP seems to know a lot about the etiquette of the aristocracy that is unaccounted for. If the voice told him all that, you do not mention it. If not, I don't see where he got it; he spent his time in the library reading legal books, not Miss Manners.
Overall, an interesting story and a promising beginning. Sorry for your recent injury. Burns are No Fun.