Hi,
You may want to look at a couple of things to help you answer your own question:

In the zephyr folders;

\boards\arm\bbc_microbit\board.h

It has the list of defines and corresponding pins

The other useful information would be a clear view of the actual physical pins: 

https://tech.microbit.org/hardware/edgeconnector/

I'm sure you will be able to make some progress with this info.

Billy..