It is impossible to predict exactly what the job market will look like when you graduate, but - in general - you can increase your chances of finding a history teaching job by completing broadfield social studies certification or by being willing to move out of Wisconsin and Minnesota for your first job. It may be possible to complete your student teaching out of state. The College of Education and Human Sciences has programs that place student teachers in states with a great need for teachers, such as Texas.
If you want to complete a coaching minor, that is fine, but it probably will not improve your chances on the job market in Wisconsin since it is not required to coach middle or high school sports in this state. Most K-12 coaches in Wisconsin have not completed a minor. Completing a coaching minor may mean that it takes you longer to graduate. Some states do require coaches to have a coaching minor, so if you plan to teach in another state and you want to coach, you should look into the requirements in that state.
Completing a minor in special education or math may improve your chances of finding a job, but it may also take you longer to graduate, so you should think very carefully and talk with your faculty adviser before making that decision. An increasing number of broadfield social studies majors are completing an additional certifiable minor prior to graduation. Along with completing the additional coursework, to get certification you will have to take a Praxis II test in the area of your additional minor (provided it has a Praxis II test). You can check your UW-Eau Claire Catalogue to see if the minor you want to do has a Praxis II. Most certifiable minors do. Library science does not. You can learn more about Praxis II at the ETS website. There is only one Praxis II test for History and Social Studies, so if you complete an additional minor in a social studies area, you do not have to take another subject test.
In-service teachers are required to engage in continuing education, so you can also choose to complete additional certifications while you teach.
Completing a masters degree will NOT improve your chances of finding a job. Once you complete a graduate degree, a school district will have to pay you a higher salary.