1. Composite bard charts are also called component bar charts, and the difference between these and compound bar charts it explained in my free lectures working through Chapter 3 of our free lectures notes.
2. Tradition costing lets the cost determine the selling price, but that may mean that the selling price will be so high that customers will not buy. With target costing we determine what a reasonable selling price is first, and let this determine the maximum cost we can afford. This is again explained in my free lectures.