Anyone care to mention a major religion which doesnt start with the foundation of a marriage ceremony?
Actually the 1st Amendment declares that Congress shall make no law regarding an establishment of religion one way or another. In other words the federal government can neither call for the establishment of religion nor forbid the states from doing so. All this amendment does is remove the question of religion from federal jurisdiction and reserve it to the states.
Not necessarily true. Jurisprudence over the 14th Amendment has led to the incorporation doctrine. This doctrine holds that the Bill of Rights applies to state governments as well as the Federal government. Under that doctrine, a state cannot establish an official religion any more than the Federal government can.
You can agree with the incorporation doctrine or not, but it is well established in judicial proceedings and it is not going to be overturned any time soon. The states cannot and will not for the forseeable future have the power to establish an official religion.