It's all possible if you can write code for it if you find the current code lacking for what you want.
The FC's have many different RC input protocols. Use any of these that your device of choice can output. PWM, PPM, SBus, DSM, etc. with several more added in the up coming release.
GCS has joystick capability built in and that can be used to control the vehicle from a PC if you have an RF telemetry link set up.
OpLinks can be configured to act like an RC PPM transmitter / receiver.