One would first have to establish memes as a scientific discipline - something that has not been done. Memes are a conjecture, nothing more.
Huh? I don't think I understand you here.
First, memes will never be a "scientific discipline," any more than cats, or levers, transistors will. They may become an object of study of a scientific disicpline, just as cata are an object of study by biology, levers by physics, and transistors by electrical engineering.
But the existence of "memes" is fairly well-established. The original defintion of "meme" (Dawkins, 1976; 1989) is simply "the new replicator, a noun that conveys the idea of a unit of cultural transmission." That culture is transmitted is uncontroversial; that culture is transmitted partially by replication is also uncontroversial, and the individual ideas are termed 'memes.'
So there is rather obviously a meme (or meme complex) for atheism, since I could teach the basic beliefs and arguments of atheism to you and thereby convince you to believe those ideas.