Hi
Thanks for your job posting.
Recently I have developed the iPhone app similar yours.
That app works to create the video from photos and musics.
I created the video from the photos and merge the video with music.
I had to list and download the musics from Cloud.
The app manager can upload the audio files to the server via FTP. And the app can access the files via HTTP. So the app can list the musics and download the musics via HTTP.
Server has a XML file contains the information of the musics. The app can get and list the musics info(music info, album image, artist name and so on) from XML file.
Once the user selecte the music, the app download the song file and play it.
The app has 100MB cache.
This app make my client really happy. And this app will soon approve to the App Store.
So I can say that I can implement all of your requirements.
I will wait for your good message.
Thank you