Well the second question was answered that I see so lets expand on the 2 questions in question 1
1) Member Galleries seems to be just for selecting which grouping, by member name, the photos uploaded by them. But you can also select that "Member Galleries" for uploade. How is uploading to "Member Galleries" different than uploading to any of the other categories?
Members gallery is a placeholder for all photos
You show all photos by a user there instead of viewing photos via category
2) If I want to have a category that ONLY I can upload to, how do I do that. Right now I have "Mike Davis Arrowhead Collection" set so that only administrators can upload to it. But how do I do this on a member by member basis.
Permissions are assigned on a usergroup by usergroup basis in Admin => Edit Categories