Hey, I was wondering. I know that the artist who submits his work under non-commercial can waive that as a permission to someone, but what about all the other non-commercial samples and a Capella that was used in the song, would the person seeking to use the music have to contact all the sample and Capella creators and get permission to use their samples, which were also submitted non-commercial?

Yes. That’s one of the complicated parts of waiving commercial rights to a piece licensed BY-NC, is that you’ve got to go down the remix chain, and get all the rights to the samples, unless of course those samples are already CC-BY.