Western Digital - WD 1TB Elements Portable Storage USB 3.0 Model WDBUZG0010BBK-WESN - Black

I would guess not, as Dish is proprietary service, you can all them and ask them.

Sure, any external HDD will work with Time Machine back up...as long as it's formatted in MAC OS Extended (Journaled) or NTSF. I prefer NTSF because it's MAC and Windows compatible, meaning you can use the stored files on both types of computers. If you only intend on using the back up files on a MAC then the OS Extended would be the better choice. To read and write on an NTSF drive with a MAC you may need to install a driver, I use Paragon NTFS. It depends on your MAC, newer systems have the necessary drivers installed.

Yes....It works GREAT. Using it for that purpose with GREAT success.

Yes it will, USB has always been designed with backwards compatibility in mind so even though USB 3.0 connector is different from the 1.0 and 2.0 connectors, it will still work with them. You simply will not be able to benefit from the speed 3.0 was designed to produce.

Unfortunately, this needs to be reformatted to do anything with Mac OS. You can partition it to work with both but it will need to be reformatted to be able to do so.