How do I add a list of members
Theres a widget called "OG members" that could help you.

When in a space, you have this button to personalize the display. Click it then you can add widget (the '+' button). In the new window, you can find widgets that you can add and configure as you need. 
Theres one called 'OG Members' in the category called (I think) 'Panel panes'.
I think this widget is meant to display members of the space you visiting