Will this plug directly into my factory wiring harness?

Yes. This assembly is designed as a direct replacement for the OEM unit — it connects to your existing harness without adapters or splicing. Power up and you're done.

Do I need to remove anything else to swap it in?

You'll need to access the interior trim around the third brake light to disconnect the old assembly and mount the new one. Check your service manual for trim panel removal steps specific to your Expedition.

Are there any special tools or fasteners I should have on hand?

Hand tools are all you'll need for trim removal and installation. Bring a trim panel removal tool if you have one — it saves time on the interior clips. The mounting hardware that secures the assembly to the frame is standard automotive stuff.