I would like audio for streaming video to be available through smartphone...APPLICATION:Waiting room environment...Listen to audio through your smartphone/headphones. How can I accomplish this at a modest cost?
"Waiting room": You should not expect your users to be computer- or smartphone-savvy. The easiest way to do it is to create a web page, and host a web streaming player inside. If you provide for WiFi at the premises, you can host this locally.
Asking your visitors to download, install and configure DLNA player (and you will have to provide instructions for that) would be way above average user' capabilities.