Google DFP is currently implemented in our website but out of the TiQ and is in Front END XT code. Is it possible to setup a Google DFP connector in AudienceStream using an external tag (implemented outside TiQ as a Front END XT code?
First, you will need a way to get the data into UDH, and the Collect tag is the easiest way to do that.
We have a Collect HTTP API to do that. See: https://community.tealiumiq.com/t5/Customer-Data-Hub/Tealium-Collect-HTTP-API/ta-p/16893
Once the data is in UDH, you can then enrich Visitor attributes, manage the audiences and fire the connector actions that are relevant.