Legality of usage - music -do you know?

Question:

Can a song be bought off Pond5, then go through some audio tweaks, then have lyrics added to it, and then be sold on itunes?

If not, it could be used in a video thats sold on itunes and used on youtube for profit sharing?

Is it that a song must be used in an "audio-video" context only?

You should address this question directly to P5 officers and to the artist who uploaded the files.

It is "derivative works" you speak and it is not allowed usage according to "Pond5 RF license" (3c - Restrictions of Use):
http://www.pond5.com/legal/license
But you may distribute "complex" work (video, presentation etc...) that includes a music track (with some restrictions - 3c - Restrictions of Use).