Getting around a tethering block with European prepay SIM
June Fabrics PDA Software Support responded:

You can try this and see if it works:
1. Install PdaNet 5.1 on both your Moto E and Moto X
2. On the Moto E open PdaNet and activate "WiFi Direct Hotspot"
3. On the Moto X open PdaNet and tap "Connect to a PdaNet Hotspot", 

See if the two can establish connection.


This suggests that this software, if added to both phones, would allow the tethering that I would like.

Further investigation suggests that there is a cat and mouse game going on between carriers that attempt to block tethering and apps that are designed to get around these blocks.  Originally there was an app called "FoxFi" that used wifi mode.  Later Android versions (after 4.0 and on) have been selectively removing the ability of wifi mode.  But there are two other modes: bluetooth mode and usb mode that are available in the more recent app called "PDANet".