In general, the type of sugar used will affect the end product in baking, and substitutions don't tend to work well. .... if you are making the baked kind i think granulated might be the best to use,...
Powdered sugar is a combination of sugar and cornstarch. Granulated sugar and powdered sugar is not interchangeable
It depends on what you're making. If its a brownie, sure. But if it is a more complicated recepie, I wouldn't replace an ingrediant.
Yes, in fact it will dissolve faster. You may have to adjust t he amount used as the volume of sugar in a teaspoon will be slightly different.
No. One is a powder, one is granular