I do not believe there is any special connection between pedophilia and incest. The Westermarck Effect works for pedophiles just as it does for teleiophiles.

But one thing confuses me: When discussing this common "incest" you excluded parent-child and sibling relationships. There is no single definition of incest, but these are the two types of relationship most everyone agrees on. Our ancestors frequently lived in small towns where most people were somewhat related, and so almost all sexual relationships were between cousins of some sort. Marriage between cousins is even legal in many U.S. states, and in many cultures it has been preferred - though in some cases with some confusing rules (where, for example, a marriage to one's mother's sister's child might be taboo, but a marriage to one's mother's brother's child was not only accepted but preferred).

So, what exactly do you mean by "incest" if you are not talking about parent-child and sibling relationships? Just nieces and nephews?