sound: Does it work with other distros? If yes, we can find a solution on TC for sure. There are also cheap, few bucks USB sound 'cards'. Most cases they have only mono input but it is good for fldigi, sstv, etc. except I/Q SDR receivers. I'm using one with a Raspberry Pi and just works fine.
Regarding reuse of old staff there are cases where simply better to throw them away and use a small SBC like Raspberry Pi or Beaglebone Black but there are many others. We are running for example at HA5HRK two WEB SDR systems, one is RPI other is BBB with FunCube Dongle Pro+. They took cca. 5W only, no HD, no coolers, no noise. Just doing the job.