Let Americans leave and then we will see how things turn out. Sowing anti-Iranian and anti-Pakistani feelings in Afghanistan will not work since it is a land locked nation and will always need us. It is better for to be our friends than our enemies. Land locked countries at enmity with their neighbors will always remain at civil war and poverty as history has shown time and time again not only in Asian continent but also in African continent.
Once US leaves Iran and Pakistan will be in opposite camps. Not on same side.
Taliban vs ANA if things manage to hold or Taliban vs Northern Alliance if things fall apart .