I trust all is well.
GREAT plugin! I love it.
As the owner of a multisite network it would be great if the network owner (Super Admin) could set default redirect links (to social media presences owned by the multisite network owner) and then when an Author inserts their personal sharing links, their personal links override the default links set by the network owner.
This feature would allow a network owner to activate sharing links on your plugin for all their owned social media presences even if an author does not have an account on one of the social sites AND an author is then rewarded by allowing them to override the default sharing links set by the network owner simply by entering their personal links.
We have a network wide Ad sharing plugin from WPMUDEV that works similarly like this and its great.
If developing multisite compatibility for your plugin is problematic, then perhaps consider adding the same feature at the individual site level with the site Admin being able to set default sharing links and lower level user roles being able to override the default links by entering their own personal links.
This would be a powerful feature for Super Admins of multisite networks and for Admins of individual sites when they are considering using your plugin on their installations.
I would even throw in some development $$ to help the multisite feature along.
Thanks for considering this feature request on an already excellent plugin.