Roamio basic audio out for late-night listening

I would like to use my bluetooth wireless earbuds late at night to listen to my TiVo and not disturb the rest of the house.

My Roamio basic is hooked to a sound bar via optical audio from the Roamio. Unfortunately there is no bluetooth transmission capability or even an earphone audio-out jack on the sound bar system.

I'm thinking that I could purchase the composite break-out cable for the Roamio, then hook the red and black audio to a bluetooth transmitter, and then I should be able to pair my wireless bluetooth earbuds to the transmitter. That should work for anything playing on the Roamio, whether it's a streaming app or playing back a recording, correct?

Two questions:
1) Are the optical audio and the composite breakout outputs both active at the same time?

2) Would the breakout cable really be necessary? I wonder what would happen if I just plugged in a 3.5mm audio plug into the jack on the Roamio? I see the breakout plug has four bands on it, presuming one of them is for the video. Just wonder what would happen if I just plugged in the bluetooth transmitter's 3.5mm plug into it since I don't care about the composite video...but I certainly don't want to screw anything up on my Roamio!

Here's the hardware I'm thinking of:

Breakout cable (which actually costs more than the bluetooth transmitter!):
http://ift.tt/1PUvRe7
Bluetooth transmitter:
http://ift.tt/1hGTxaT
Adapter:
http://ift.tt/1PUvPD7

Thoughts, anyone? Am I on the right path?