Well, "GPIO" is not entirely correct word in this context. What we have is an expansion header with pins, where some pins are connected to the SoC and used for general purpose input/output (GPIO) and some pins are directly connected to the power supply. The real GPIO pins can supply very limited current and are used for just receiving/transmitting data or lighting a LED at best. The power pins are what you are interested in.
Yes, if your Raspberry Pi Zero uses a decent power supply and you use jumper wires to connect a +5V power pin on the Raspberry Pi to a +5V power pin on the Orange Pi PC and also connect a ground pin on the Raspberry Pi Zero to a ground pin on the Orange Pi PC, then both of these boards will be working fine and sharing the same power supply.
Yes, if your Raspberry Pi Zero uses a decent power supply and you use jumper wires to connect a +5V power pin on the Raspberry Pi to a +5V power pin on the Orange Pi PC and also connect a ground pin on the Raspberry Pi Zero to a ground pin on the Orange Pi PC, then both of these boards will be working fine and sharing the same power supply.
