Ok, to answer your three questions:
Availability of the announcement Feature:
I am waiting for results from one beta tester before I submit the update to the app store. Once it is submitted, it takes Apple about four days to approve it and add it to the store. I would expect it should be out by Sunday or Monday of next week.
Copying the player config between devices:
There is an option to export the configured setup of the application which includes all player names, numbers, and song titles, from the entire app. That export ends up as an email attachment that can be opened on another device to import. There are details for that process on this forum in the FAQ board under title 'export/import'. The destination device would need to have the exact same songs (by title) as the original device because the app cannot transfer the actual songs. The actual music is all managed by the iTunes library on each device, you would just need to add the same songs to the itunes library of both devices.
Playing only parts of the song:
Yes, that is pretty much the entire premise of Walkout Song DJ and why I wrote it in the first place. Walkout Songs are generally only about 11-15 seconds long and usually a chorus or something along those lines. When you add a player and a song to the app, there is a configuration screen to allow you to pick where in the song to start and how long to play from that point. When it reaches the end of the configured duration it does an automatic fade out. The start and duration of each song is part of the configuration that would be exported and imported to another device so you should only have to set that up once.