I'm not too sure if the Untied Nations has the power to enforce churches to do much in changing their non-compliance toward open acceptance of gay rights, such as enforcing the marring within the churches.
Accordin to the report, so far as I recall they only expect them to teach the rights of gay people and a contraceptive. I'm not sure they necessarily expect them to perform the marriages. Also, I agree with you, the UN doesn't really have any teeth. So the deadline given of 2017 seems strange, you know? I'm wondering what exactly they are going to do, if anything.
This may just be my opinion, but gay rights and religious freedom can't coexist. I feel this way because the primary religions of the world rely on sacred books that are thousands of years old and cannot be changed. These books condemn homosexuality. Thus the religions preach against homosexuality as immoral. It's fundamental in the foundation of their faith. If religious freedom exists then we have groups that become, essentially, hate groups inculcating intolerance.
i just don't see how they can coexist. I expect religion to be forced into a minority like groups such as the KKK. Except much worse, since these groups will view it as persecution and that will just fuel the fire.