I think this is a great list and you hit the nail on the head! I think the one thing people don't think about when starting their own business is they will have to wear multiple hats like you said. The business is never has cut and dry as you think it is going to be and you will have to do everything when you first start!
My advice is to think of 20 tasks that you will need to preform and then think of 20 more because you will need to do all of them at some point. Being self employed is awesome and starting a business is so fulfilling but understanding what you are getting into is really important!
Great post!