FYI I have this speaker selector
and this receiver
So you can see I have the one port on the left that needs to connect to the receiver.
FYI I have this speaker selector
and this receiver
So you can see I have the one port on the left that needs to connect to the receiver.
That AVR doesn't have a Zone 2 output, which would be preferable. More preferable to Zone 2 speaker output is Zone 2 line output, which allows you to use any amp that would connect to the RCA jacks.
One thing you didn't mention- do you want to control the volume in each room, or just live with whatever you get? Most speaker selector brands are available with level controls, or you can install a level control in each room, somewhere between them, in a closet, etc.
You need to realize that whatever the output of the amp- the speakers are sharing it unless you use an amplifier that has separate channels for each speaker and if you want the system to get up and go, you need power. Not twice as much, not three times as much, you need to determine the level you want and find out how much is needed, based on the speakers you plan to use. You may find that each speaker needs 50W and with four pairs, that's a total of 400W, which that selector IS NOT going to handle for long, if at all.
If you do decide to buy an amp with a channel for each speaker, I would look at Parts Express, for their Dayton amplifiers. They turn on when the signal reaches the input, the channel pairs are bridgeable and it's reliable. I have installed two and one went into a house 9 years ago; the other was originally in a bar and eventually, to a fitness facility.
BTW- don't assume that you need the distributed sound to be in stereo- it doesn't. You're not doing critical listening in those areas, so mono will get the sound there and you won't have to listen to ping-pong vocals, which is apparent if you listen to the first Beatles stereo records. If the amp or AVR has a mono setting for the extra zone(s), use it.
If you really want the best sound in multiple locations, it's best to have a separate system with better speakers in each, with some way of sending the audio from the source end to each. You can use many methods- Cat5e with an audio distribution amp is a fairly reasonably priced way- jacks are available that allow terminating Cat5e on the back and connecting RCA cables on the front. Belden 8451 and Belden 9451 are thin shielded cable and will work for analog audio feeds- jacks are available for properly terminating this type, too. Parts Express has the cable and jacks.