"The problem is that none of the TVs has a USB port."
Probably because they are not Internet TVs.
What it should have said was "simply plug into the USB socket of your computer or Internet TV". An Internet TV has a computer inside.
If they are not Internet TVs than you ain't gonna connect them to a LAN.
In any case there is no way that you can connect to a LAN via a video port (which is what VGA and HDMI are).



