I made some sounds for 1.2 which some of you might remember. Since the links and svn for the 1.2 sounds seem to be broken now I'll post up the links to the sounds here. Use them as you like where you like under the terms of the licensing.
The license for each of the sounds are found in the contents of the file SoundList.txt in the attached pk3's
If there are some of these sounds that need additional work then let me know.
Yes, after we've thoroughly checked the quality and appropriateness of the sounds. Some (to put it lightly) sounds are horribly inappropriate for their selected use. It is a good starting point.
Yes, good point. I'll set up a formal system for sounds that are fine and those that need to be replaced from the SVN repository to allow those who wish to contribute a starting point. I'll have it up in a few days after we release Alpha 5.