Those who build computers like Orangepi are digital electronics designer or analog electronics designer?
If there are both of them in their team, which parts of the board building is done by digital designer and which parts are done by analog designer?

Is it possible someone with one of the skills(digital or analog) does everything by himself? (I mean how is the percentage of the needed knowledge? if 95% is digital and 5% analog, we can say he can learn that 5% to do everything himself(without knowing much about analog))

Also is there any other skills in their team?