I could live with restoring one source about Dolby joining and about Porterfield, but since that information is not negative, it is not vital to source it. As far as lecturing, that's a classic case of WP:BLUE, since that is part of a college professor's job and we don't need to cite such an obvious statement. As far as Porterfield, I'd say it's better to delete it, as it is nothing more than name-dropping.