Can I cancel enrollment at a university I deferred enrollment at?

I am planning to take a gap year. During my gap year I plan to join the army reserves and do a semester of community college in the spring. I have been accepted into the University of Minnesota, if I defer my enrollment for a year can I apply to other colleges during this gap year and switch universities and terminate my enrollment at Minnesota or will I be locked into the school once I choose to enroll and defer admission?

Also follow up question, what is the amount of credits im allowed to take at community college without getting my admission recended? I know some schools if you take a gap year you’re not allowed to take more then 12-14 credit hours during this gap year. Does anyone know University of Minnesota’s policy on this?