A:AnswerIt will chop anything you put in it. If you use it to chop vegetables, I wouldn't run it more than 1 or 2 seconds. It'll liquify the vegetables.
A:AnswerI don't think u can make dough but u can use it to grain other things that u might use for the dough or its cookies or a cake. Blend the fruits for an apple pie etc.
A:AnswerI don't have Ninja 1000 to tell you with 100 percent certainty. But my experience says that even blender jars of different models of the same manufacturer are normally not exchangeable. I would, therefore, assume that you would not be able to use Ninja jar to Oster or the other way around.
A:AnswerYes majority of blenders you can buy the knifes separate. Just go to bestbuy or online from the manufacture of the blender and you can order parts.