Woooo! Challenge fic!
For reference, this takes place the year after Deathly Hallows, and assumes that everyone had to repeat that year. (hostile takeovers by magical Nazis tend to harm the educational experience, you know)
Hermione was quite sure that Communicationse Withe Thee Deade was not seven hundred years old, sorry, "sevene hundrede yearse olde," partly because of the not-at-all historically accurate ye olde worde-endinge E, but mostly because her research showed that studying such magic was a good way to get burned at the stake in those times. Most likely, it was produced sometime within the last twenty years, and made to look medieval to appeal to the surprising number of people who thought all the best magic was invented before indoor plumbing.
That said, it was a good resource, and a quick test showed that her desired spell did work exactly as described. So she carefully penned out three letters to the three deceased individuals who she believed most needed to hear from her.
Dear Lily Evans-Potter,
You're probably happy just knowing that your sacrifice saved Harry that one time, since, well, it was kind of the entire point. I don't know if the afterlife has any kind of windows (metaphorical or literal) back to this life, but you're probably aware that it saved his life three or four more times after that (though you're probably not happy that he kept getting into situations where he needed to be saved like that). And I don't know what kind of organization the afterlife has, so it's entirely possible you haven't seen the Dark Lord (particularly since he split his soul seven times before he died, so he may not even have gotten there), but if you have, then you'll know that your sacrifice is part of the direct chain of events that lead to his second downfall.
I'm just writing to tell you that, even though Harry gets all of the credit - not that he doesn't deserve acknowledgement, he did take down the Dark Lord! - I know that you should be known as someone who contributed to keeping the wizarding world safe. Even if your intention was rather more specific than that.
Sincerely,
Hermione Granger.
She stared at the letter for a few moments, not entirely sure whether she really wanted to send it. The possibility of the letter reaching the wrong dead individual was... well, not mentioned in CWTDe, but she couldn't help but think that nobody would have known if it had happened.
She decided to put off the decision by writing the other two letters first.
Dear Peter Pettigrew,
All right. You know you're a cowardly rat, and it was completely horrible of you to sell out Harry's parents to save your own skin. You've probably heard enough of that to last you eternity.
So you'll probably be happy to know that your cowardly actions were part of the direct chain of events that lead to the downfall of the Dark Lord you fear so much.
You'll probably always be known as a bad guy, but you'll at least be known as a bad guy who somehow helped bring down the Dark Lord. So you don't need to try to haunt us or anything. I'm pretty sure it doesn't even work like that, but if you find some kind of loophole that lets you come back even though you decided to move on, feel free not to exploit it at all.
Sincerely,
Hermione Granger.
Wow. That came out completely differently than she was expecting. She might want to rewrite that... In the meantime, she would write the final letter.
Dear Severus Snape,
... I just don't get you. Even in retrospect, even knowing your motivations, you're really completely incomprehensible.
You wanted to protect Harry for his mother's sake. Fine. But why did you have to be so horrible to him? I know, I know, his father, but...
Nothing you did makes any sense, except the parts where you were working against the Dark Lord.
She stopped. This wasn't coming out right either. She shook her head. Guess that's just part of dealing with the dead, she thought, and put quill back to parchment.
I don't even know why I'm writing you, really. I guess... to thank you. For helping bring down the Dark Lord. You probably knew it would end with him killing you and you did it anyway. So... thank you.
Sincerely,
Hermione Granger.