I think I have worked out how they are doing the Fedex tracking bit. If you take the Fedex tracking number you have been given and put it into the Fedex tracking website but change the last digit you can look up the next Fedex tracking reference. You can look up lots of tracking numbers on the site and if they are not actual tracking references they will return a message that says
"No information for the following shipments/FedEx® Office orders has been received
by our system yet. Please try again later or contact
Customer Service."
However, if the tracking number is for an actual Fedex shipment, it will show you the details for that shipment, including the recipient city. Then you can click on it to see the progress of the shipment. There is no login or other authentication needed so you could just write a piece of code that looks up consecutive number on the website and returns the details for each one, put them in a database and search it when you got an order for a drone to find a reference with a destination city that matches the buyer's city. So the buyer is looking at tracking info for a genuine shipment going through Fedex to their city but it is not for the buyer it is for some random stranger who is getting something real shipped through Fedex to the same city. This would explain why it takes a day or two for the drone company to send tracking info. They are looking up sequential Fedex numbers until they find one in the same destination city.
I reckon this is definitely a scam and when I look up the Fedex tracking number I have been sent it is due to be delivered by 18:00 today. I will be absolutely stunned if it arrives as no-one else's has.