Here is how to connect to an ethernet cable without WiFi.
I have no idea if Apple officially supports this. I have not tested. It's been reported as working for several years.You may get an error message. Ignore.
There are multiple youtube videos reporting that you can connect an iPad via Ethernet cable.
https://www.youtube.com/watch?v=2ndUO_p_9oI
see suzyfromoz on the last page of
How do I connect my iPad to the internet when only a wired connection is available? Thanks
You need
-- apple Camera connection kit
-- powered USB hub
-- apple USB to Ethernet connector.
[ yes you need apple connectors ]
Would be an interesting test if you could get more than one iPad to work off the same ethernet cable via multiple apple Camera connection kits.
Here are more ways and examples, google:
ipad connect ethernet cable
example
http://www.gottabemobile.com/2014/08/28/how-to-connect-an-ipad-to-ethernet/