UNIHIKER M10 with two distinct power sources: USB-C powering Arm Cores + microbit breakout board MCU

What really intrigues me  about the Unihiker M10 is its ability to connect to micro:bit breakout boards. DFRobot suggests a couple  micro:bit breakout boards that work with the Unihiker M10. My question is: 

Will micro:bit  breakout boards that try to supply their own power (3.3V) to the MCU via the edge connector work with the Unihiker M10?

Context:

• Many breakout boards like DFRobot's Multi Function Expansion Board for UNIHIKER M10 / K10 & micro:bit provide their own power source. In STEM projects, I like to use Elecfreaks' Nezha Pro Breakout Board (wiki), which contains its own Li-Ion battery. • To the best of my understanding, it is not recommended  to connect chips and MCUs via the same bus, when the chips are powered by independent power sources. If the connected chips share a common ground, one can use a logic level converter to make sure there isn't any current flowing between the chips and damaging them. However, if there is no common ground, connecting the chips through a shared bus especially complicated. DFRobot's breakout boards work around this by providing an USB power supply port on the breakout board, which the Unihiker M10 connects to. So at least there is a common ground. • The Linux platform in the Unihiker M10 (running on the RK3308 Arm 64 cores) requires to be powered via USB-C.• Then, there is the MCU portion of the Unihiker M10 platform, which connects directly  to the micro:bit breakout board. However, most common breakout boards (incl. the Nezha Pro) are designed to power MCUs directly via the 3.3V pins on the edge connector and do not provide an USB power supply port to connect the Unihiker M10 to. 

 

Therefore I am wondering whether in the Unihiker M10, the MCU is electrically completely isolated from the RK3308 Arm CPU? Is a common ground between both required? Schematics would be great, but I didn't find any for the Unihiker M10 (only for the Unihiker K10, which does not contain the linux hardware stack). 

Thanks, appreciate any insights and help.