Molex 503398-1892 is the correct socket, however there are other components that need to be soldered. I counted 5 10k resistors next to the micro sd socket.
2 filter caps under the shield and maybe others.
So soldering the micro-sd socket is not preactical :-(
You would have to look at the datasheet.
It has 2 serial interfaces.
I assume one of the serial interfaces is for data transfer while the other is for control.
So, if you use serial to USB converters, you should be able to connect both to an USB hub and connect the hub to the onion.