Like a previous poster, I think middle names that end in A seem a little too rhyme-y with your last name, even if they don't actually rhyme. Does that make sense? Of course how often do you really say all three names out loud together... so maybe it doesn't matter much.
From your most recent lists I like all of these:
Grace Lauren
Grace Angeline
Grace Isabelle
Note: minor modifications because of my bias against ending in the letter A as mentioned above.
Let's see, initials would be:
GLN
GAN
GIN
Any preferences or dislikes there to help you narrow things down?