MPNG 2.0.1 R4 follow me (lead mode) implement

Hello everyone,
I have to make a quadcopter with a follow me mode in my grad project. Let me explain a little bit. I am planning to use xbee 900MHz on the user and the quad. User has a wrist module with function buttons. When user calls sends a call signal to the quad, it has to hover(in stable or loiter mode) itself, fly through the user and switch to the follow me mode(lead)(For safety reasons RC radio has to operate at the same time). Another functions will be loiter, pos_hold, RTL and land. (as you can understand, my instructor wants it to fly autonomously) I prepared my quad by using rc timer crius v2 with mpng 3.0.1 R4 code and ublox neo7m GPS. Now I have some questions

  1. Is this configuration suitable for this application? If its not what can you suggest(do i need a bluetooth module)?
  2. How can I implement follow me mode to the main part of the code?
  3. I am planning to write the necessary codes to the user code section of mpng 3.0.1 code. Is it ok to define xbee library only to the arducopter part?
  4. For the hovering part how can I set a throttle value for a decent amount of hover? What I mean is what should I write as a command?
    5.For instance when user presses loiter button the code should be like that or what?

if(loiter==1) // or case MAV_CMD_NAV_LOITER_UNLIM:

I would appreciate for any help.