AirPort Extreme as multiroom audi solution

I wanted to clarify some points as I too have a whole house system I would like to set up.

My situation: Whole house is wired for approx 10 zones speakers in wall/ceiling, home run to basement central area.

I am considering Airport Express with a Dayton Audio MA1240a Multi-Zone 12 Channel Amplifier or something like that.

I would have 1 Airport Express per zone.

I have 1 mac Mini that would be a media server, as well I have a DNS 323 NAS that has a itunes media server option. My Apple Remote App sees both libraries.

I currently use airport extreme with mac mini so I cant really test everything out yet.

But I want the following

each zone: Airport Express + Amp (MA1240a or equivallent), speaker wire and pair of speakers.

It sounds like I cannot play from one iTunes library to multiple locations as separate streams, ie different music to each zone.

If I used an Apple TV instead of Airport Extreme, would that change things?

Also, since Airport Express is Airplay compliant, each iphone, itouch or ipad can stream whatever source they have on their device directly to their zone. Most likely, (4 kids in the house) they would have all the media or streaming services on their ipad that they would want to hear anyway.

Any additional thoughts on this?