Still cant tell if the analog and digital outs are variable or not. (On pg 37 under the Recording heading, it does not ask for the volume to be turned up, so I assume the are fixed) The manual states that only 2 channel PCM audio is available on the digital audio outs. So if you are playing multi channel audio via digital input, it will only send L, R signal to digital outs if the incoming signal is decoded by the source. Also, HDMI and Component signals cannot be cross sent. So your main display will need both connections if you have sources that have a mix of the two video connections.
A better option is to run analog L, R and get a 2 channel AVR to drive the zone 2 speakers.
But, this still leaves the zone 2 video to be handled.
IMHO, the 154 is not geared towards multi zone and therefore it makes the task at hand difficult. Upgrade time

.