Hey Bill,
I'm too old to truly provide helpful advice about school districts in Dallas, my kids are all grown. DISD constantly is being investigated by the State. The FBI has been involved over missing and/or fraudulent spending of federally funded money for over a decade. You can google the latest debacle. Its all about perceived power and the cash. It appears the average student is left behind - far behind. Texas isn't known for its education system. Most of the blame should be placed on society and the parents, not the teachers and the school district.
Knox / Henderson is a nice area. Your probably going to find you will want to commute from one of the suburbs.
On the music scene, like most parts of the country, it is not as big as it used to be. Deep Ellum was the King, the West End Marketplace used to be the King, before that it was Lower Greenville Ave. Trees, The Granada Theater are probably the two best venues. As far as major acts touring they all stop here at one of the mega venues. Lots of local bars and local talent. It's not Austin but the Dallas Music scene is fairly good. Used to be great but so was Fort Lauderdale in the 80's with rock clubs - nothing stays the same.
Good luck to you and your family on making a decision to relocate.
Best wishes,
Hamerica