Maria was the hardest, as she didn't make terribly many decisions in her short, pre-RP existence, and none of them were exactly large - the one that is basically wouldn't change her much. But I decided to go with the idea that instead of the standard Silent Hill ending that is her in-game canon, instead of being rejected by James and that whole epic fight, she's now going to be as though the Maria ending took place. Which means she's a lot mellower, not so much a bitch, and isn't obsessing over James all the time. ;)
Henry never moved into South Ashfield Heights. He never went through anything that happened in the game. Which means he'll be a lot quieter, a lot less likely to stand up for himself, and just.... softer, I guess.
Myre never challenged her brother to a duel at the end of the first book. Because of that, her Lair never split, she wasn't shunned by her mother, and she's not so prejudiced against 'two-leggers'.