Hi, Miro,
I did the presentation at Pi and More last weekend
on how to access GPIO pins.
With the current state of Fedora on Pi, the typical talk would be: take one of the standard projects (starting from LED light, motors..) and try to implement them on Fedora. And it is going to be a challenge already.
GPIO support is more or less doable, but then it comes to PWM, varios digital I/O channels, hats and so on..
Thus my main message currently: Fedora is not going to be easy, but it is for the better. Building smth with Fedora means building smth with new kernel. You are navigating unfamiliar waters, but this exactly makes it more interesting and _awesome_ than just building yet another boring weather station on Raspbian.
From low level topics the most interesting would be the device tree overlay support. How it supposed to work, what works and what doesn't, what is the roadmap for it. But I don't know the details myself, so maybe Peter Robinson (CCed) can provide some insights.