I have successfully been able to integrate a Share Extension (iOS >= 8) in a Cordova project by using XCode.
However it is kind of painful because it requires to version the xproj file, or to add a manual procedure that the developer must do in XCode after running cordova prepare ios
It would be nice if it was more friendly to create an iOS share extension on a Cordova project.
I know it may be hard to reverse-engineer that xproj file so it is probably not a priority, as there is also a workaroud.
I have documented my steps here: