I had a friend growing up whose name was
Gabriella, and she simply didn't have a middle name, which spoke volumes for her character. But it's a nice break between the first and last names...
Gabriella Rose (it's on your list!!)
Gabriella Adelle (I don't think the "ll"s are too much, and I personally prefer
Adelle to
Estelle b/c it sounds more youthful and lively.)
Gabriella ChristineGabriella AniseGabriella Reine
But I do think you should reconsider the "a" ending stipulation, because
Gabriella Sophia is my favorite. ;)