Seems after going through the process of figuring things out yourself there is this forum, awesome by the way but my first post was going to be about the audio from the TV coming through ONLY the TV itself in NOT coming through the Jensen head unit like you'd think, but eventually figured it out.
Seems FR just hurries through the 2 HDMI cables when hooking up the system during assembly, since it sounds from this link not all were having the problem. But the TV itself has 2 HDMI ports, one that is basic that receives audio and video (HDMI 2), and one that receives audio and video, AND has the ability to resend audio (HDMI 1) back to the head unit on the wall. It's kinda like a two way street with information, whereas its bidirectional. This type of input on the back of the TV is called ARC (audio return channel).
Seems even Forest River Tech support was not aware of this, but they should be paying attention to it since to hear the TV through the main system, you have to have these HDMI cables attached properly, and the input settings on the wall unit set to "HDMI ARC". After you do that, wow awesome sound, and loud to even hear over the air conditioner.