Nobody, you should pray for their fans instead. Unlike these idols, the fans haven't been murdering people, m-lesting them, sacrificing/consuming children, and using their blood to feed the obsession of being young. But these idols did. And no average person, like all of us, can comprehend just how deeply terrifying that is and the effects it will have on your soul. They all have demons. Multiple. Their name is legion for they are many.
Of course if you still have the urge to pray for them I won't stop you, but these people are evil to the core. Personally, I believe some people are just meant to be that way; and if that theory is true, praying for these demons is unnecessary. Once you sign that contract, you're in a covenant with the evil one. You've already made your choice. Should you betray him, you will either receive intense programming from his other servants or simply die.
Well, what I'm trying to say is, there's no point. But do it if you want. I highly recommend praying for their fans for they are simply under a spell and have not done the horrors their favorite celebrities have done.