1. Not required, but you should if you want to clean up your sd card.
2. On stock there should be just Nintendo 3ds and dcim folders.
3. Fat32. It's recommended to use guiformat. Don't use Windows built-in format.
4. Yes!
5. It doesn't matter
Thank you very much for the speedy and helpful response. Now I just gotta wait for my flash card to be mailed. They are closed now due to the holiday but are shipping it February 21st. I can’t wait lol