"If there are no biblical prohibitions for Gays to be in leadership then there should be no prohibitions for pedophiles either."
I don't support practicing gays in leadership either. However, the literature on children and sex offenses is quite clear about their less developed capacity to consent, and the horrible harm. There's also the matter of high recidivism by sex offenders. There should always be prohibitions or constraints on pedophiles for these reasons.
For each of the reasons you site, there are arguments put forth by folks like Nambla to contradict them. Who is to say that having nonconsenusual sex is harmful if it was done in a more inclusive and accepting society ? Who is to say it isn't our ancient prohibitions that harm the child and not the act itself ? Who is to say that having young sex handled lovingly by a person who feels love for the child could not be a positive and affirming experience ?
You have concluded that nonconsensual sex at a young age is harmful without acknowledging that the harm may be from the guilt we make the child feel. Much like the guilt we make a homosexual feel. There is no telling how a child would be affected in a society that looked at this differently.