I manage the hardware for a friend pilot too. He has a Nexus7/GNS2000 combo same as mine, also an iPad where we couple the XGPS160A. I don't see there would be any problem with GNS and the iPad.
If you already have the iPad, I would order a GNS2000 from one of the major on-line retailers. If it doesn't work, you can send it back within 30 days. On the SkyDemon forum you can get plenty of help to get it working.
The GNS2000 is quite a bit smaller than the XGPS160A. On the XGPS you can fairly easily connect multiple Bluetooth devices (up to 5, I tried 3).