I finally got everything working. For now. I bought the second controller separate from the I1 v2; but here are a few things I know make a difference:
1) You have to first link the second controller to the Inspire as a Master using the red button on the UAV. Once you do that the second controller gets a name RCxxxx and a password. Turn off that controller.
2) You have to turn on the first controller, set it in Master mode, and relink it to the Inspire. Be sure that it operates and has a video feed. If you do all this indoors you may be getting interference from your house WiFi.
3) Turn on the second controller, and set it to slave. You have to search for the Master, then request control from the Master.
4) If you get a video feed on the slave you have succeeded. Almost. I had to set the Master to free gimbal control. On the slave left stick right/left yaws the gimbal, and right stick forward/reverse pitches the gimbal.
This is now working for me with DJI Go on an Android NVIDIA on the Master and DJI Go on an iPod on the slave.
Just holler if anyone wants some pictures and a slower walk through.