The "queer folk" descriptions evidently referred to the shady-looking southerners dispatched by Saruman. At this point, Saruman is not seeking the vengence for his fall that culminated in his subjugating and ruining the Shire. He was importing "weed" to Isengard at this time, but was he also seeking news of the ring at this early juncture, and apparently had some news of the Hobbits' journey with it.
The incident in the main hall of the Prancing Pony and the knowing looks and smiles of some in the room when Frodo disappeared suggests these southerners knew about the ring and were presumably charged with intercepting it. However, none made any effort to do so. Only the Nazgul attempted to take the ring in Bree, and they must have been informed by the southerners of its presence at the Inn.
Saruman was in league with Sauron, but only superficially. His ultimate intent was to obtain the ring for himself and displace Sauron as Dark Lord. Why would Saruman's servants tip off the ringwraiths as to where the ring was? The Nazgul would have delivered it to Sauron. Or were these southerners possibly in the service of Mordor rather than Isengard?
I am not sure that there would have been time yet for a specific order to go out from Saruman... I think the crooks in Bree like Ferny were working for themselves for a buck or a favor, more than they were following any organized plan as yet from Saruman.