With all due respect, kids in Chicago were doing the fist bump when I lived there 10 years ago. Its an urban thing, NOT a Muslim thing. Only folks in Outerwhitelandia would think that it is some sort of Islamic symbol.
I believe that Barack and his wife are seculars. Obama was raised by an atheist mother, and as a "buppie", doesn't really have a strong attachment to "laws of mer-say" religion.