I liked this movie and the group of girls (and one boy) did too--girls age 9 and 10. Most gave it a "10"! A couple of the girls said it was a little scary and they cried--but mostly because (spoiler alert) they thought the Mom was going to die. My 5.5 year old boy wasn't scared at all, so I think this is likely to scare sensitive boys and younger girls. In fact, my boy laughed a lot more than the girls (it's that boy humor that is all over the story).
This isn't the best Pixar movie--but the animation is beautiful, and the message is really good. I love how it resolves with regret, an apology and forgiveness. This is "real life" for pre-teens and teens. If you are not ready for your 5 year old to see someone talking back, than this is not the movie for you. And mothers and daughters fight all. the. time. Though she is disrespectful, she pays for it in consequences. That's a good lesson for all of us!
As for the cleavage/key thing--it was a little weird and inappropriate. But I would say it was not done in a sexual manner. It was approached like a mischievious boy would approach it. And the animation bums? I guess they could have left them out, but I find your American beach to be much more suggestive and with a much higher sexual element than those cartoon bottoms. And most of us take our kids to the beach, right? Don't get me wrong. I'm very conservative about things like this, but these are minor things especially considering most young kids aren't phased by a naked bottom.
I thought it was a good movie; better than Cars 2 for sure--not as good as Monsters or Toy Story 1. But compared to all of the other junk out there? This is much better. But if your child is scared easily, you should wait until they are about 9 or 10.