I don't necessarily think she is a brat, I think Natalie doesn't want her to grow up as she enjoys having a little girl and doing all the things that typical toddlers and then little girls like doing with their mums - baking, shopping, cinema (not play parks as she moans when she has to go and get cold, tho fine to go on walks on her own in her new Adidas gear!). Calling her "Belly" as well, it's a very childish nickname - my little girl who is literally weeks younger than Annabelle has already said to me she wants me to stop using her baby/toddler nickname and that isn't even anything I'd consider too babyish.It's weird yes. Particularly as she isn't a slow child. Brat Yes but she seems fine in her development. Both my kids use normal cutlery. We give them the blunt knives from our cutlery. But as long as you teach table manners not to eat off your knife there shouldn't be a problem.
I always had the impression she didn't really want a boy/boys and definitely not twins, and as such she doesn't want Annabelle to grow up and start acting her age which comes with a natural turn away from parents and more into friends, play dates and independence. Once that happens, she will have to face reality that boys don't act the same way most of the time as girls do and she will have to accept there will be more rough and tumble play, less girly stuff etc.