Hey Kurt! I personally have gone through this dilemma myself; deciding whether to double major, what major to choose, if you want to specialize or take on a minor is very stressful.
To put it bluntly, you can major or double major in any subject you want and still be accepted into PA school. While double majoring does make you a well-rounded and unique student, it will undoubtedly be more work then if you major solely in Microbiology. Unfortunately all graduate school programs, including a Masters in PA studies, requires you to have a competitive GPA and test scores to match. If you don't have those minimum requirements, the admissions council won't even give your application a second glance.
This may seem too practical, but if you want to be accepted into a PA program your first time applying, you would have a better chance with just one degree behind your name. If you watch a lot of medicine/healthcare-related videos you may have come across Dr. Andre Pinsett, the "MCAT murderer;" in one of his youtube videos he states that it's better to have one major, some projects (activities in which you take on leadership roles) a high GPA than to have more than one major/minor, less projects and a lower GPA.
Judging from your post, it seems like you have a lot you want to achieve during your time in college. The first thing I would do if I were you is prioritize: with all the goals laid out in front of you, what do you consider the most important in the long run? Before even entering college, I promised myself I would put my academic studies first, and spend as much time with family/friends in my free time. After that, I decided to volunteer at a local medical center-- not only did it count as healthcare hours which is required by most PA programs, it also served as an outlet for stress-relief (living independently from my family for the first time and dealing with roommates really did a number on me). Interning at a hospital for patient care experience, becoming a research assistant, and tutoring kids on the side all came after I had my priorities in order.
All in all, I would stick with one major and see if you still have time to take on another major from there. The choice is really up to you! If you have any more questions about college life or what you need to do to stay on the pre-PA track, feel free to message me any time! Good luck!