The iPadMini won't have GPS if you buy the wifi only version. Only cellular models have GPS, useful if you plan to use "follow me" or reset the homepoint after the drone has left home, such as moving your location in the boat, etc. IMO, having an iPad Mini with WiFi only is a nuisance. There's enough other things to do when flying, I don't like adding to that, having to connect to your hotspot to get maps, or cache maps at home, etc. It's just another hassle and something to go wrong, IMO. Although it costs $10/mo to connect my iPad to my Verizon data plan, to me it's worth it.
I've never used Foxfi, nor have I heard of it before. Please try it out with a friend's iPad and see, then let us know how it does? If it does what their website says, it should work.