I thought about getting that same setup..Glad the info helped some.
Sorry sir, I'm not experienced enough with jail breaking and what you'd need. I must defer to those with more knowledge.
I use a Dual external GPS for the rare times that I need GPS at the RC.
However the price of the external GPS is the same as the price difference between the WiFi and cellular ipad.
I borrowed my friends ipad mini 4 to test but it's WiFi only.
If tethering works good I will just stick to that.
Sent from my SM-N910T3 using Tapatalk