plus you could have a delicious plot with being in a relationship with amnesia and then slowly remembering their canon love interest and having SEVERE MORAL CONFLICT
i gave her all her pre-death memories back first because otherwise.... she would be like "not taking memories. i'm eventually going to die. no thanks."
I actually have only skimmed Files once. So I know there IS a character in Book 4 that appeared in it. But I can safely say that you don't need to read it before hand to understand
NO INTEREST UNLESS IT BENEFITS HIM. Ronwas created/developed to earn Hermione so. Piper-- She's HPPILY married and remembers that