Speedie, I think I've followed what you're looking for, and unless there's some factor that isn't being mentioned, it appears that option 3. is the simplest, most direct way to get it. There's nothing "patchwork" about it; using an old 5 or 7 channel receiver(say maybe about 80-100 watts)and selecting all-channel stereo mode is as you note a typical "party" usage and does the job needed.

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Enjoy the music, not the equipment.