How did you know Teledji didn't have permission of the Guards? "I have urgent business with the Sultana"

If the Monetarists wanted to shelf Nanamo she probably would never had gotten to full adulthood. However Ul'dah works on a balance of power in many ways and while they manipulate things and control most of the finances of Ul'dah, they still are subject to the opinions of the people. More over most of the power in Ul'dah already sits with the Syndicate. It is very hard for Nanamo to do much without their agreement. Teledji wouldn't have been able to prop up the Sultana as a puppet ruler because A) the other Syndicate members wouldn't allow it since they all have their own competing interests and B) the people would riot.

The whole thing was set up to legitimise Teledji's arrest of the WoL. It wouldn't be hard for him to set things up to have a legitimate reason to be visiting the Sultana at the time, nor would it be strange for him to have bodyguards.