Hi Sam, Thanks for helping me out ... Let me try and answer below:
1. Does Amkette EVO TV 4K has the ability to pass through (bitstream) over HDMI. I could not find anything on the website. All it says Digital Passthru over Coaxial (SPDIF).
It detects HDMI Passthrough. I can play DD+, DTS through Kodi. In fact, their stock media player was able to bitstream a m2ts Dolby Atmos file (not DTS X though).
2. Is downmixing is happening in all cases. I mean even if you play a locally stored file on the device itself. (or just on Google Play Movies or other online streaming content)
Yes whichever file has PCM 5.1 , it is getting downmixed. For local file or remote file (not Google Play movies), I got Kodi to transcode PCM 5.1 to DD AC3.
3. In Kodi, under settings - > Audio Out put do you see the option DD capable reciever available and selected along with ofcourse enable passthrough selected.
Yes, I see both DD capable and DTS capable and I checked them both.