The question I have is what would they be missing if they use a separate receiver for the two zones (which they already own) vs. a multizone receiver? As far as I can tell:
1) both current receivers are pre-HDMI, so we would have to forgo running everything through the receiver. Plus this adds more cables to the components vs. everything using hdmi
2) extra space required in the cabinet for two receivers vs. one
3) don't believe they could use same universal remote for 2 audio receivers (but could be wrong)
4) won't be able to run tv sound out to patio...only radio from secondary receiver
5) no AirPlay without AppleTV..not sure would be used, same with new features like Pandora, Sirius, etc.
Am I missing anything that would be of benefit with one receiver?
(1) and (2):
"Zone 2" is usually another set of pre-amp output, not HDMI, doesn't route HDMI input (until now in some models), 2CH, so you do still need a pair of RCA cables and a separate power amp, unless perhaps in some higher models where you can assign a pair of unused rear speaker terminals.
It's possible to output audio via HDMI using "TV out" (not "zone 2") to another AVR but you need to go to the menu to change HDMI output destination. Some AVRs will only output 2CH via HDMI.
Long runs of RCA cables would be much cheaper than HDMI of certain gauge, plus possible signal loss and HDMI handshaking issues between two AVRs.
(4) might be possible depending on what output the TV has.
Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.
I have a Harmony 900, which is more remote than I think you are referring to, but I have the old receiver defined as a device so I can use it to change the volume...
Based on your description, I doubt they would use airplay much.
I sold them on AppleTV for AirPlay at the very least and the other features will be a bonus. It turns out I was "selling" the idea of AppleTV to the wrong parent;) Looks like it will be a nice setup for them even with their current hardware they had in their old house. Thanks again.