[Fire TV Themes and Apps] KidJoe:
Just some follow up since I've been away from this thread for a while...

1. I've seen a few posts mentioning to just use MoviesAnywhere (MA). Keep in mind, this thread was started BEFORE MoviesAnywhere, back when it was still DISNEY Movies Anywhere which only supported Disney, Pixar, Marvel and Star Wars movies, and linking your Disney library to iTunes, Amazon, Vudu, or Google Play.

2. With the advent of MA, while it connects to UltraViolet (UV) compatible services like Vudu, MA only supports 20th Century Fox, Sony Pictures, Universal Pictures, Disney and Warner Bros. It does not support Paramount, MGM, Lionsgate and possibly others. MA it does NOT support UV directly.

3. The only UV movies that will show in MA are those that are marked as both UV and MA compatible... For example, visit Vudu and look at the listings for Terminator: Genisys or Transformers: Age of Extinction.. they are marked UV, but not MA. Movies like this do NOT show in MA, nor across the linked services like Amazon, Google Play, iTunes, etc. for playback, and therefore a UV compatible app/service like Vudu or FandangoNOW must be used to play them. As a result, I have quite a few UV movies that I could not play without Vudu or FandangoNow apps on my Fire TV. Compare that to the Vudu listing of Ready Player One, where you'll see both the UV and MA markings. Movies marked like this ARE available across services. They can be watched in any service linked to MA such as Vudu, iTunes, Google Play, Amazon, FandangoNow, etc.

4. The Android TV Vudu app works to watch any UV or MA movie in your linked libraries, even the UV only titles that are not available via MA.

5. Since the initial post, Vudu still doesn't show under Recent Apps on my FireTV's menu... But it continues to show under Apps & Channels, and you can move its icon anywhere. I moved it to my 2nd app, so its the main Fire TV home screen.

As mentioned in the OP, I have two different 2nd Gen Fire TV boxes. Here are the versions of the Vudu app I've been using on them.

On my 2nd Gen Fire TV Box connected to 1080p TV... this newer version of Vudu works fine for SD/HDX (UHD is not an option due to the TV) and also provides 5.1 audio per my Pioneer Elite VSX-21 receiver (see OP)

air.com.vudu.air.DownloaderTablet_4.1.45.96620-1236620_minAPI21(armeabi-v7a)(nodpi)_apkmirror.com.apk

https://www.apkmirror.com/apk/vudu/...android-tv-4-1-45-96620-android-apk-download/

On my 2nd Gen Fire TV Box connected to UHD TV... this version works and also plays UHD/4K movies... (as mentioned in the OP, this box is only connected to the TV, and its info display says Dolby Digital Plus)

air.com.vudu.air.DownloaderTablet_4.1.23.60526-1200526_minAPI21(armeabi-v7a)(nodpi)_apkmirror.com.apk

https://www.apkmirror.com/apk/vudu/...android-tv-4-1-23-60526-android-apk-download/

NOTE: when I tried 4.1.45.96620-1236620 on my 2nd Gen Fire TV connected to UHD TV, it failed to play UHD movies. They looked like they were starting to play, but they immediately exited back to the previous menu. So I rolled back to 4.1.23.60526-1200526 which still works for SD/HDX/UHD movies. I have not tried any other more recent versions, and likely wont until 4.1.23.60526-1200526 stops working.

I have not done any further testing on my Gen 1 Fire TV boxes.