To be clear, what you have has been industry standard for whole house audio for 30+ years. It's not dated, and whole house audio hasn't had any major infrastructure changes in the past 40+ years. You run wires to speakers in walls or ceilings and pull it all back to one central location. At that central location you take the wires and terminate it into a amplifier of some sort.
Bare wire ends would be very common to leave behind as the amplifier in use may have used phoenix type connection which takes raw wire into them. So, when you take off the connectors, you are left with raw wire ends. That's VERY normal.
Since all speaker zones are labeled, you then just need to put in a whole house distribution system of some sort. You can do this using a single amplifier hooked up to a single source if you would like, or you can get more creative and use more advanced systems.
Because you have 7 rooms, you run into some issues with whole house audio systems that often stop at 6 rooms, or come in groupings of 6 rooms. That is, if it costs $1,200 to get 6 rooms, it doesn't cost $1,400 to get 7. It will cost another $800 or so because you need a significant hardware jump.
But, in the SIMPLEST form: You can get a single amplifier and just plug a source into it, tie all the speaker wires together (properly) and run audio out to all the rooms. The impedance matching volume controls, if they are setup properly, will not overload the amplifier and you will get audio playback in all rooms.
If doing this, I would likely use a speaker terminal block to connect all those wires into...
Whole House Audio Stereo 8-Zone Speaker Distribution Module
czh-labs.com
More advanced would be to use an amplifier which can drive all the zones with their own discrete power. This would come from a 16-channel audio amplifier.
The CP-1650 expands the capabilities of an RTI AD-4x and AD-8x Audio Distribution System easily and cost effectively. The amplifier utilizes Cool Power® technology for superb sonic performance, pumping out 50 watts per channel - doubling the output power of an RTI audio distribution system.
www.ebay.com
These can be had from about $400 or so on eBay. But, you want to be sure they ship with the Phoenix connectors so you don't have to go looking for them after the fact. The bare wires terminate into Phoenix connectors directly and they are a commonly used item in whole house audio (WHA) setups.
There are also systems which are available which can offer phone control. Where you can get rid of the in-wall volume controls and drywall things up. Then go to a system which exclusively offers you the ability to choose from different audio sources and to playback different things in different rooms if you would like to. These cost more and have a bit more time involved in the setup, but are a bit more future leaning as a technology. But, at the end of the day, they still just playback audio in the different rooms.
As a shameless plug, I do encourage you to feel free to give me a call if you happen to be in the DC area. For what it's worth
@WaynePflughaupt was not actually correct as I know I've helped some get resolution to their problems here, and I did have one person call me up and I went to his home and installed a WHA system for his existing speakers that is working really well for him. So, it depends on how deep you want to dive on this.
