Okay, so I can't speak to the H8 itself, although based on the recommendation in the other Q5 forum where someone from futeko recommended the H8 since it runs Kodi natively and not in a wrapper from what I could understand, I can confirm that DTS can be transcoded by a player. Here is what I did:
Based on reading the Kodi forums, I could tell that there is a setting in Kodi that asks whether a receiver is DD capable and DTS capable. In a sub-setting for DD capable, it asks if you would like things transcoded to DD (AC3).
I downloaded Kodi for my macbook... then using the SPIDF mini adaptor plugged into the headphone/digital port, I connected to my AVR in our main room. I played a file that has DTS-HD... with the setting in Kodi for transcode to DD (AC3), the DTS-HD file displayed on the AVR as being Dolby Digital. I confirmed via listening with my analog audio analysis equipment (aka, my ears) that there were unique sounds coming out of the surround speakers as would be expected in the scene on that file. I also tested the same thing flipping the settings to indicate that it was also a DTS-capable receiver, and the AVR showed DTS on the display and had the same results (sounds where you expect them).
The only thing I haven't done is try this on an actual Sonos PlayBar (my friend has one so I will probably bring my computer over and give it a try) but from reading in another forum entirely, someone was using Kodi with a PlayBar to accomplish this.
I know that getting entirely different equipment may be a good option for some folks, and I am indeed annoyed like many others that the PlayBar can't do DTS... but this is a great option for folks who for whatever reason are using this PlayBar in a 5.1 setup and want consistent Dolby Digital surround. In my situation, the wireless music in this particular room is important and it is very family friendly to use.
I don't know that I can trust the H8 to do this since I have not seen anyone show that it can. As stated in the Q5 forum, they recommend even using a Raspberry Pi running Kodi... so that is what I am going to do... ordered the Raspberry Pi 3 along with a Digi board that provides SPIDF connection.
Anyway, good luck to others... can confirm that "native" Kodi transcodes to AC3 (which is seen as Dolby Digital 5.1 on receivers and still sounds great or at least good enough for some people).