[Zubersoft]

You can still use the IP address under which the Chromebook is connected to the router in order to connect other devices to it. You just have to use the "Direct Connect" option and enter that IP address. It should work perfectly fine to connect two Chromebooks this way. 

You are right that I should probably detect when running on a Chromebook, and display a warning the first time the user accesses one of the features that needs a WiFi connection (Connect Tablets, sync library or connect to companion).

Mike