I have the p2 and the wife has just purchased the fc40. Question is, if we fly them together will they interfere with each other's frequencies? She will be using the I phone app on hers!
You'll be fine. The wifi issue is having a strong 2.4ghz source located inches away from a 2.4ghz receiver. The wifi signal strength from a iPhone on the ground and an unamplified camera on a neighboring quad aren't going to swamp out the P2 signal (or vice versa).