Official comment
The information you're looking for is on page 6 of the user manual.
- No, there is no limit to the size of the drive. If there were a limit, it would be included in the manual where the other limitations are listed.
- Yes, the manual clearly states that you must format your drives FAT or HFS+ and that NTFS is not supported.
- Yes, all drive sizes.
- Yes, you can do this in Windows 10. A quick Google search will help you find out how.
- Yes, it is possible, but you are losing most of the functionality of the product.