A:AnswerYes. However, the PS4 does not support any game data to be saved on external devices such as this. You can store movies, photos and music files on this for use on the PS4 however.
A:AnswerYes, you can. Steam will allow you to store any or all of the games in your library wherever you choose, including an external drive. However I would recommend you connect using USB 3.0 if possible to maximize performance.
A:AnswerThe drive meets all of your requirements except that it gets it power from the USB cable. If your DISH receiver doesn't provide power through the USB, it may not work.
A:AnswerYes. Plug it into the console and do the console format to it, then move all of your installed games to it and make it the default drive to save to.