I think בובת פרווה should be accepted as stuffed animal
I think so too, I don't think anybody says חיה ממולאת.
Yes, the Wikipedia article בובה ממולאת defines: בֻּבָּה מְמֻלֵּאת הִיא בֻּבַּת־פַּרְוָה.
What's the difference between זו and זאת?
Well, זֹאת was the usual form in Classical Hebrew, זוֹ in Mishnaic Hebrew. In modern Hebrew it is a question of style, which to use. Some think זוֹ should not be used with the definite article.