Take the sound servers and throw them out the door.
Better yet, persuade the developers of these sound servers to make their servers output sound via JACK instead of opening /dev/dsp directly. Sound servers are convenient, but they are completely unusable when they claim the sound device for themselves. Making the sound servers into JACK clients would allow them to all get along while allowing other JACK applications to run at the same time.

For stupid applications that insist on using ALSA PCM interface or /dev/dsp directly for trivial sound outputs, use a wrapper in similar design to aoss to redirect the output to JACK.