I like this question. If it is a true religion then it should not be based on faith but facts. It should be transparent and show how those who run things have been given the right to do so by god or whomever. People shouldn't be left to guess or have faith that they have the right just because they so. What makes any religion different from a business corporation if people are appointed by other people rather than divine intervention?
The one true religion, would have to have something that sets it apart from all others. It would need to be widely accessible by the majority. So by definition, be inclusive, not excluding.
The principle God, of this religion would intervene in mankind. Would be worshiped, as the one true God.