Cable-driven parallel robot (CDPR)

I need to run 4 cable robot system on rapsberri pi 3(fell free to suggest a better solution), so raspberry pi3 runs stepper drivers and reads analogue joysticks, or any hobby radio transmitter with cppm\pwm output. All kinematics equations will be provided if needed(it`s opensource). Feel free to port any existing Arduino project. I got following questions 1 - if there is enough outputs on raspberri pi 3 B to control 4 stepper motors, and if it`s possible to use expansion (HAT) boards. 2 - What is the better solution to operate this machine?, i need 2 joysticks to control horizontal plane and to move it up and down, so it`s better to read joysticks with raspberri pi through ADC converter or it`s possible to connect regular RC transmitter via its cppm / pwm output so it will work wirelessly let`s say from turnigy 9x transmitter without any modification and raspberri pi3 will just read cppm signal and we can control up to 8 parameters through 1 wire. 3 - i have 4 stepper drivers drv8825 sitting on arduino cnc shield v3, we also can use it if needed. The only thing i don't want to involve is arduino because it`s lag, i need to avoid delays on joystick reactions.