I have not read all the replies but here is my contribution!
Your pup is normal, she has only been home for a very short time and she really does need to settle in first before she can start taking in all the rules. Thats not to say you shouldn't keep doing what you're doing, consistency is key and every time you think you are going around in circles, do not worry, you're not!
If you're spending more time outside than inside trying to make sure she has no accidents then you are doing the right thing. The first week, two weeks, 6 months are going to be tuff and they are going to require your almost full time commitment.
This is just my opinion but the whole 'shaking head to rip up prey' thing they do is so normal. I do not see why you think you have to tell her off for that. I'd let her get on with it, train it to a command (this can be fun), when I play tug of war with mine I actually encourage him to do that! You are certainly worrying over nothing.
Just remember that lots of socialisation with other dogs and people is what will teach her her manners not telling her off for playing with her toys.
Most importantly, love her, enjoy her! They don't stay that little for long and you'll never take enough pictures sure you take as many as possible!!! Oh, and videos! Don't forget videos!!!
Good Luck
edit. and of course Merry Christmas and obviously Happy New Year!
ooh, edit edit.
I just re-read, i missed the bit where she snapped at you.
You really need to take charge and so does the rest of your family, she needs to know she's at the bottom of this particular hierarchy. That is super easy at the moment because she is a little pup. Make sure everyone enforces the same rules, if one person does not, then she will pick up on this, they are far from stupid and will take advantage if they are allowed to!
A firm no, removing her from the room, pinning her down till she's calm, stopping play, bitting her ear? all of these work in my opinion and so does a bunch of other stuff so pick what works for you and your family and stick to it.