Deep linking is required or not for a channel having single live stream ?

Ha-haa, that's a good one!
i don't actually know how such demand is to be verified - but it should be easy for you to provide a "pro forma" (dummy) implementation - since regardless what params you are given, you would be playing the same content. In fact, i don't think you have to do anything at all and it already satisfies the requirement by default, no? As long as you are not acting on launch parameters any different than no launch parameters and just play your content...

As an update, i asked a RokuCo insider and his reply - "if the channel launches straight into the live stream, the dev doesn't need to do anything as the launch args can just be ignored" - seems to match my understanding.

Submit for publishing and let us know if app reviewers raise this as an issue? Would be interesting to follow

I just submitted a live stream audio channel. I also asked them if content id's were required for deep linking. Its just 1 stream with no additional links.
I should find out in a day or so.