With regard to her various titles, it would seem appropriate to stress in the first place the common denominator of all these designations. In Jesus Christ, God spoke a human language. Similarly, Mary facilitates the understanding of the central message by highlighting facets of its actuality. Also some of the physical make-ups of Our Lady are not due to her express wishes but to a close collaboration between visionaries and painters. Both have their own perception of things, thus the difference and relative subjectivity as to the result.
Visionaries are human and fallible.
Their sometimes very personal way of understanding the message and the messenger is instrumental for the emerging of a specific designation. They reflect our attempt to put a face on the apparitions and to give it a name. Apparitions are not an article of faith. A good introduction to the biblical Mary would be much easier and show that Catholics and Protestants have many common beliefs about Mary.