There would be a subtle difference in taste between the two cakes, as well as (perhaps) a bit of difference in the rise. The more important difference would be in nutrition. Butter is a natural fat, while shortening contains partially hydrogenated vegetable oils which have been proven harmful to health.
Vegetable Shortening
Yes, that would be just fine. A shortening agent can be any of various fats such as butter, lard, margarine, and so on. So, butter is shortening.
No...especially if you are making pudding, butter or shortening melt at a low temp and you will have a heavy, greasy result
To keep from melting the butter, margarine, shortening .etc.
For most things. Let it cool and the finished product will be slightly heavier with shortening.
Flour used for pie dough is all-purpose flour. This flour type is versatile for making a pliable, dense dough that will keep firm.
In bread, shortening coats the starch molecules, which slows down staling after the bread is cooled. Shortening can also be used to lubricate the baking pans. In cakes, shortening helps prevent too much gluten formation, which gives a softer, lighter cake. Shortening also helps incorporate air bubbles into the cake to help with rising.
Yes, just know there may be some difference in texture. Shortening has less water so melts slower allowing more rise time and a higher and lighter product. Butter has more flavor but melts at a lower temperature so will spread out quicker and add a crispier texture. If you do interchange do so in equal amounts 1 cup of for 1 cup of the other. Make sure you read the recipe closely in case it says anywhere "Do Not Substitute". If you have this in the recipe there is a reason so do not try it.
not for creaming sugar or for making a laminated dough. In general vegetable shortenings aren't that healthy and should be replaced by butter.
Yes, and it is probably better for you. Shortening is made with hydrogenated fat, which we probably all should try to reduce in our diets. The results will be a bit different. Butter will add a bit more moisture to your recipe. If you are baking your recipe, such as cookies, you might want to add an egg. The egg will prevent the cookies from spreading too much and add a cake like texture to them, similar to the "crisp outside, chewy inside" results from shortening.
I use butter for mine. It comes out of the oven very fluffy and light.
Any solid shortening will work. The finished product will vary a little bit in flavor, but should be acceptable. For tea biscuits, I would use butter or margarine for flavor. Crisco or other vegetable shortening will work but I would stay away from animal fats.