Luna

This fanfictions started off great :)
But yaio is usually something I look for in fanfictions that or asexually main characters :)
Nice idea thought :)
Have fun writing :)

I like the story

HermionexHarry. 'Orion' is Sirius. Sirius ORION Black, maybe?

I vote for Daphne

I'd like to say that this has potential... but unfortunately can't. Sorry. The basic premise is nice, interesting and does have the aforementioned potential. The fic doesn't. You're plagiarizing SAO light novels, rewriting them almost word for word, and changing just names. There's no meaning in inserting HP characters into HP-themed world, when that world is a carbon copy of Aincrad and the characters speak, think and act firmly like their SAO counterparts, up to straight stealing lines. That's just wrong.
As I said, the basics have potential. Rewrite it with at least HP characters acting somewhat like themselves, and already that would be a great improvement. You can do thatchap 4 is written roughly along those lines. Now, for some particulars. Chap 2: 45k pounds for a gaming device? No. Just no. It's ridiculous. Most cool overspec'ed gaming rigs cost no more than 3kand that's pretty much the top of the top. You can't expect even wealthy gamers to buy it, no matter how exclusive SAO is. 1-1.5k is the absolute top of the reasonable price range. Pairings: see above about the characters. No point in assigning names, when they're going to wear Asuna's mask. For canon characters on the other hand, and if you're still pursuing general SAO plot, Hermione fills Asuna's shoes nicely, being somewhat similar. Daphne is a blank canonically, only gaining character in fanon.
Anyway, hopefully you'll take my advice to heart. Waiting eagerly for a rewrite.

Good story enjoyed reading it I hope you have an abandoned it

Great crossover story so far, as for pairing just Daphne no harem, although I think Luna could make a good Yui, look forward to the next chapter(s), update soon.

You should have had it as the mirror of erised, it would have fit with the harry potter theme better, but mirror of truth is from the anime/Manga so it's still cannon sort of,

My vote is for Harry to pair up with Luna :)

Asuna as a pairing

If there is characters from SAO I think he should get with Asuna

... You basically took sword art online, transplanted Harry Potter into it and changed almost nothing in terms of fights and character interactions? It really is quite tacky using the same exact set pieces from SAO without really changing anything... I'll follow the story to see where you take it..

Daphne greengrass for the pairing

Little nitpick. The game's name is nonsense, and not in the way that the english doesn't make sense.

SAO, Sword Art Online's name comes from, I'm pretty sure, the term "Kenjutsu," of the characters for "sword" and "technique." The second is a bit iffy. The word is also translated to 'art,' so 'sword art.' Of course I may be wrong, and if so, oh well. Now if you are going to use magic, there are a couple of ways to do so. 'Majutsu,' first character from "Mahou" plus the same second character, but because of the way japanese is, "mahou" is literally "Demon Law." Going by the animeenglish, it would be called either Demon Arts, or from 'Mahou,' Demon Law, Demon Rules, Demon Etiquette, Demon Method, something like that. Being a little poetic, you might replace 'demon' with something like ifrit, something like that. The character "ma" in "Majutsu" means magic in context, so Magic Technique/art, but then again, "kenjutsu" means swordsmanship in context but is turned into Sword Art. So it would probably be one of those, plus 'online' at the end. Basically, look up a word's characters, and mix and match. That's almost certainly how some Japanese teenage writer named it when it first was written. Ah, but there are other words to mean magic. They, following the above methods, though, are even worse. 'bewitching technique,' 'charm/curse technique' The only one I could come up with that really flows... well, I'll leave that to the end of this.

So, sorry for the wall of text, basically, the title 'sword art online' comes from a literal translation of Kanji. It's bad English, and a similar name would be derived from either 'mahou' or 'majutsu,' probably, with a funny outcome. So, either do it, with a dumb name or don't, and come up with a better one.

A more plausible, though still weird name could be like "Witch System Online." Sounds catchy enough, no? Well, if not, you could just ignore the source name, and make your own.