Whole wheat bread flour should have a protein content of 14-14.5%. Look at the nutrition label. Find the grams of protein per serving. Next look at the top of the label and find the serving size, also expressed in grams. Divide the grams of protein by the grams per serving. That will give you the protein content of any flour. What are you making, by the way?

it depends. A way to tell is to look at the ingredients list. (Bread flour usually has a protein count of 14% or more. The flour should be ground from hard red spring wheat for highest count.) For example. my bag of King Arthur Whole Wheat flour is labled "Whole Wheat Flour" not "whole wheat bread flour" but it is milled from hard red spring wheat as per the ingredients list. The King Arthur white bread flour is labeled "bread flour". The are both milled from the same hard spring wheat, but the label on the front might mislead you on the whole wheat into thinking it was not "bread flour".

No -- whole wheat bread flour will have more gluten, meaning doughs made with it will be more elastic and chewy.