Ed Cobb's estate get's 100% of that. Because it's just a cover, Cobb is the only credited songwriter. The Rihanna song was written by two music producers, but it was built around a sample of Soft Cell's version. That means, even though it samples their performance, they don't get money, Ed Cobb's estate shares it with the two songwriters.
I never heard Marilyn Manson's version, but I heard his cover of Sweet Dreams (Are Made of This).