I have been following all the treads, including this one regarding the Litchi app and fpv. I have had the MP for a month now and have resisted from using the app entirely until today... bought the app a few days ago and got familiar, took the Mav for a cruise in Fpv mode and it ran like a dream on two seperate flights (2 batteries used). I kept it out of immersive mode and also the mode with camera tilt, using all input from the RC. It was awesome. I did a lot of research and I am aware that there are some compatability issues between the dji update and the litchi app but this is just a success story- no issues during flight: All input from the RC to the drone was decisive and the camera was not laggy whatsoever, hovering with the app was smooth even with a slight wind.
If anyone out there is in the same predicament I previously was, worrying about Litchi FPV and using the Mav; this control setup with a spotter the whole time was a success.