These resources will help you with finding information about potential sources of income from owning a horse and doing a cost benefit analysis of keeping a horse at home vs. boarding a horse for Part 3 of your assignment.
University of Maine Cooperative Extension article about different types of horses and how to select them based on your needs, as well as information about costs for horse ownership.
University of Tennessee Institute of Agriculture Extension report about expenses for owning horses, including information about boarding vs. self stabling costs.