Hi John,

You can create a role named say "limited editors" or whatever you want to name it.

Then in Site Settings you can add that role to "Roles NOT Allowed to edit feature instance settings" from Site Settings > Security >Permissions

Then you can go into the feature settings for any existing content instances and add the role as an allowed edit role on the instance (not on the page). Users in roles with page level edit permission can add items to a page but users with only permissions on the feature instance cannot.

Unfortunately there is not a way to automatically grant this edit permission on feature instances, it would require a more privileged user to create the instance and configure the edit roles. There is nothing to do it automatically for already existing instances.

Hope that helps,

Joe