1 switch-bank, 1 rotary, 5 inputs, 3 devices, no idea how
first of all, you have to make sure that you can work with ONE lcd, ONE rotary switch, ONE set of buttons, ....

Structuring your code in a modular way helps greatly here. for example, your lcd code would look like this:

  lcd_init(LCD1); //initialize lcd1
  if (rotary_read() = ROTARY_2) lcd_puts(LCD3, vBuffer); //display vBuffer on LCD3 if rotary 2 is selected
  btn_state=lcd_readbtn(LCD2); //read the button states on LCD2