I just wonder if you have plan to add some hooks at admin option page and some other places ( described bellow ),
file name: invite-anyone/admin/admin-panel.php before line 98,
A filter can be used for $settings_fields variable.
same file before line of 384, an action can be added to extend more list item there, this can be done for other options too.
invite-anyone/group-invites/group-invites.php at line no 329,
A filter can be used on $friends variable before returning.
These are what I need for now, there can be more hooks used, but I am thinking to extend group invites restriction to different user types ( at buddypress user account type plugin )