1. You can take them part time, many people do. Especially with online universities such as Athabasca.
2. Honestly, med schools don't care so much about clinical experience. They want you to pursue extra-curriculars that you are passionate about and stick with them for quite some time. As for research, look for positions online kind of like when you are looking for a job. You can also contact professors at a university asking if they need assistants for their research.
3. If you have already graduated, most schools don't allow you to redo prereqs to bring up the gpa. Your gpa is pretty much set after you graduate. You can take prereqs to meet requirements but it will do nothing to your gpa.
4. Letters of recommendations do not have to be specifically from science faculty members. They can be from any prof, employer, supervisor, etc.
5. No, lots of people switch paths and go into medicine. It will not be views negatively, if anything they may see you as more matured and it will work in your favor.