Obama? Sorry, I just don't see it. In the US he's a huge celebrity, biggest for sure, but we're talking WORLD aren't we? Think of all the third world countries with a lack of communication, are they going to know about Obama? It's doubtful.
The Pope? Oh hell no, pun intended. I don't even know his name, and he's not all over the news, and he's done nothing that's really affected anyone, as far as I know. The FORMER Pope, John Paul II, I would consider, but this one? I don't think so. Think of the Middle East. Are they EVER going to put the Pope on television? I highly doubt it.
Annie Lennox, people question. Well, it's safe to say almost everyone in the world listens to music, right? And her music isn't something most people would oppose. It's not religious or political. She's pretty much legendary.