Mike,
Why contact a copyright holder on a song that may never be released? I doubt if any Record Label or Producer does that until the final songs are selected. In my example songs are submitted to a producer for a possible cut and (I would hope) the person submitting the songs knows how it works. Your example of an Artist cutting a song out of the blue with no process of pitching the song to that Artist smacks of amatuerisim on the part of the Artist. I am often amazed but shouldn't be surprised of those not knowing how the music business works. IT IS LONELY AT THE TOP!

In my case I have a song submission form, a permission letter, and a mechanical license in case a song of mine is selected for release. They cover the steps very carefully so no one is confused about what to do.

If you re-read Everett's question you can see why no one would require a mechanical license to use their songs for a demo to pitch to a Label.

If someone likes your songs well enough to make an Artist demo, they may also release them and you get a cut.

There is probably no exact way to inform someone that a song of his is under consideration for commerical release. Sometimes a song is put on hold by an Artist and never released. If the songwriter(s) are notified before hand and the song is passed on it is pretty disappointing.

If I were a producer I would not notify any one until the final selections were made. If I couldn't get all of my first selections I would have the others for backup.

Ray E. Strode