[wrxtasy]

does audio passthrough mean HD audio bitstreaming? If so, the AFTV2 and Wetek are out, though the latter does decode HD streams to PCM, which to some is "good enough."

Cough Cough, Ahem, the WeTek Core does very comprehensive 7.1 HD Audio Bitstreaming with Android Lollipop when using WeTek Jarvis mediaplayer (Kodi) as tested by hdmkv HERE

Even Dual Band 2.4/5GHz b/g/n WIFI will be sufficient to Stream Blurays over WiFi.

The Chromebox would be the fastest, pure Kodi 7.1 HD Audio device, unless you start needing to playback high bitrate 8-bit HEVC. For that you need the Hardware decoding in the WeTek Core. I believe the FireTV2 also does Hardware HEVC decoding too.

The Amazon FireTV2 would be the best for a comprehensive selection of remote friendly Android Apps, in a box that runs Kodi as well. You will get 5.1 Audio out of these Android video streaming Apps, that the DRM video Android Apps on the Core lack.

All devices will be able to Passthrough the standard 5.1 Dolby Digital/AC3 Audio over HDMI when using Kodi. They are not slow Kodi devices.