Legal Question in Entertainment Law in New York

Re: music licensing

The master use gives you the right to include the sound recording in your film. See my other answer for further detail. Does the artist's agreement with you mention anything about the group? It's difficult to answer your question any further without seeing the agreement.

Re: music licensing

This is a factual question that requires a review of the license agreement and any agreements (verbal or written) between the songwriter/singer and his band.

You may not have the consent of the band if the licensor does not represent the band or does not have sole rights in the recording as the "producer." Normally session musicians in a "work for hire" arrangement do not acquire rights in the recording unless the contract under which they are hired states otherwise. To be on the safe side, though, one needs to obtain the musicians' waivers. The extent of the licensor's warranties and representation in the license agreement would also be relevant to the question. Finally, if the musicians actually constitute a "band" for legal purposes (read, partnership), then the question becomes whether the songwriter was the leader of the band and had the right to bind it to an agreement licensing the use of a recording made by the band.

Once again, seek an attorney to help you out on this if you want your film to be marketable commercially.