For anyone else who has ethernet speed negotiation issues some routers let you set 1000/ full duplex on their ports manually. Also make sure you aren't using a cat5 cable, you need at least a cat5e or higher for 1gbit. Many short cables, the kind you might use with a device like this, that you have laying around could be cat5

Not an employee of the company but they are basically a Chinese company that manages their US customers through a PO box, It's not that uncommon. I also want to mention that it doesn't establish any cloud connections and you can verify that it's not communicating out because the device itself doesn't connect to your network. It does have it's own network configured on the port so if you also setup the correct subnet and ip you can communicate with it.

I use two WF-803M to go from the Fios ONT in my apartments hallway to my apartment and it's been working. You said your macbook is directly connected to the MOCA adapter and you're on the status page of the adapter. It's not possible to use the internet and access the network of the MOCA adapters at the same time since you are assigning your own internal IP. I don't know how this is done on a mac but you need to change to DHCP for that ethernet adapter.