Bob Iger confirmed on a Q4 call today that Disney+ WILL be available on Amazon FireTV starting on the November 12th launch date. Disney previously announced that Disney+ will be available on Android, iPhone, iPad, Apple TV and Roku devices. Additionally FX will have a large presence on Hulu including 4 original series for Hulu (available late March 2020). New episodes airing on FX will be available hours later on Hulu, and approximately 40 series (including 17 recent ones) or 1650 episodes or FX programming.
The full interview can be found on CNBC: https://www.cnbc.com/2019/11/07/disney-dis-fiscal-q4-2019-earnings.html