I like your story so far. I do have a question. Will Harry always have to say those long drawn out phrases to perform his Kido? It seems a bit impractical.
As for who to pair Harry with, just Hermione and Sam would be enough, but I like the idea of Luna being thrown in once she arrives at Hogwarts. Her uniqueness would fit in quite nicely with the Potterverse you are creating here. But you really shouldn't add any more. Authors who go with the full on Harem, it just gets ridiculous. Too many and the focus gets diluted too much.
I do hope you will explain the significance of Alex's book being different than Harry's.
I like what you have done so far, and I like the character of Sam. I don't usually like original characters in fan fiction, because they are usually bland and boring. Yours isn't. Not by a long shot.
I can't wait to see where you go with this, though I suppose I have to read the rest of what you have posted first. I guess I'll catch up with the story and then hurry up and wait.
Those long phrases will eventually shorten and completly vanish. Going by Bleach rules on Kido a skilled caster can use a spell by calling the name only and the incantation becomes simply a power booster. So as Harry gets better his need to recite incantations will reduce. He may still use them from time to time but thats only if he wants mor power from his attack. I'm glad you like Sam, I based her on a friend of mine to keep her from getting boring.