1 - More than 3 TVs in the home.
2 - The TVs are all connected to external sound systems of some sort, but not all use external speakers. (the kids TV doesn't use external speakers, the rest do)
3 - The kids TV is cheap, cheap, cheap! The rest are good, or better.
4 - No, I use a wired music distribution system in my home.
5 - Wired system, so if I were to add something wireless, it would tie in to the main wired system.