It is not possible to connect Lemur to the Lemur Editor through a MIDI interface. A Wi-Fi network connection is absolutely necessary in this case.
We introduced the Lemur In App Editor on version 4 of the app. This means that you can create, edit and save Lemur templates direct on your iPad without using the Lemur Editor. However, it's true that a few functions are still only available in the Lemur Editor.
You can always create templates in the Lemur Editor, then use iTunes File Sharing to drag-and-drop the JZML file to Lemur. You will need to have your iPad connected to your laptop with the sync cable.