Only one of the three things you mentioned is comparable to F.lux: iOS Night Shift.
> Kindle added "Blue Shade"
Blue Shade is, unfortunately, an exceedingly half-assed implementation; I wouldn't be surprised if an intern wrote it over the course of a month or two. Unlike F.lux, (or Cf.Lumen on Android), it doesn't change the color temperature of the screen—instead, it uses the same naive implementation as apps such as Twilight or Lux, which is a semitransparent reddish overlay that causes black colors to turn red. Considering that Kindles are running a completely customized Android ROM, Amazon could have done so much better.
> Android announced "Night Light"
This is only for Google Play Books, and nothing else. [1]
[1] http://officialandroid.blogspot.com/2015/12/silent-night-wit...
Android announced "Night Light" and Kindle added "Blue Shade" and iOS came in last with "Night Shift" so it appears everyone has.
When F.lux put up affiliate links hawking Himalayan salt lamps and Swarovski crystals and used "cancer" as the 30th word in a press release, I didn't feel too bad hitting "uninstall" for the final time. So Long, and Thanks for All the Tint.