1. Umm, that should fix itself if they are updated (e.g. fuzzy and unfuzzy) 2. We don't really bother deleting unused messages unless they are in the way 3. Ok.
Just to make sure we are in synch, please confirm that you are aware that all existing translations of MediaWiki:Interfaceadmin-info/en are incorrect.
Maybe some random edit of MediaWiki:Interfaceadmin-info/en followed by its undo, could force Translate to present the latest revision for translation?
Could you please remove "!!FUZZY!!" from MediaWiki:Interfaceadmin-info/en and save?
Maybe this edit will finally cause the software to identify correctly the version of this message that should be translated.