I do and I don't. I think that science just hasn't found a way to explain them yet. But I have seen them all my life, so, yes, I have to believe in them, by the tenet of seeing is believing.

If they can believe in ghosts and still don't believe in even one god, sure.

People don't always hold logically consistent positions. Atheists are not immune to disordered thinking, or to being ill-informed or un-considered on certain topics.

Atheism describes a lack of belief in one topic, nothing more. Most atheists are atheists as a side-effect of something else: being skeptics and critical thinkers. But not all. And not all apply critical thinking across the board.