Do you buy into We Are All Completely Beside Ourselves?

Ultimately, I think the success, for each reader, of Karen Joy Fowler's We Are All Completely Beside Ourselves depends on the degree to which you can buy into the premise: that the narrator, raised in her first five years w/ a chimp as a sibling, would hold onto those sororal feelings toward the chimp over the course of her lifetime - moreover, that her older brother and even her mother would as well. I have trouble believing in that - I think that the very early initial bonding would fade and that within a few years of birth the child would see the chimp as a pet, an amusement, something different - but not a sister. If you buy into that premise, much follows - and either way there's much to discuss and debate in this novel. The ending was much softer than I'd expected - yes, Rosemary, the narrator, did get face to face with her father, who put the family through this cruel experiment, but she forgives him, far too easily for such a bitter and alienated character as she seemed to be earlier on. And yes, there is a reunion with chimp-sister Fern, as mother and daughter together move out to S. Dakota to be near Fern in her lab for retired chimps - Fern does seem to recognize them - and they make a bit of a living writing children's books about Fern and about their unusual family. Honestly, I wanted more of a blow up - the kind of an ending that Harlow, Rosemary's wild friend, would have created. We do learn that Harlow became the partner of the estranged brother, Lowell, who is a wanted man for destruction of labs and other property - but the exciting parts of the novel are left kind of to the side, and the novel itself ends on a sweet, harmonic note. Much good material here; in my view a lot of bad narrative decisions, but a very casual and sometimes very funny narrative voice do seem to carry the day.