I think that whetever meals are on offer, its a good idea to take some of her favourite snacks just in case CW and F dining isn't her cup of tea (she won't be alone there!) On the return she may be better off eating in the lounges and then sleeping a little? (exhausted from all the fun things to do in BOS)
Not sure there are F PJs for children - hopefully someone can clarify
Of course, taking a fully loaded ipad or similar is also a good idea - she may get bored with the IFE so this would help her pass the time.
And howabout getting her to pack her own backpack or carry on with some of her favourite toys/activities?
Hope you have a fabulous trip!