I actually say/think VY-Uh-Let most often, then vy-let and then vy-o-let. I think it has to do with how strong my accent is that day.
Violet Evangeline is the best combo out of the lot you gave and it is certainly better than
Violet Anne (not only is
Anne not pretty, it's used too often as a middle name). I know that's not what you were asking, but it's what popped in my head when I read "
Violet Anne". But to answer your question, I think it'll be like
Daisy, fashionable but not really common and I do not know any Violets in person.
Violet is a hard name to combine and still have it sound somewhat pretty without using the general fallbacks (Leigh/Lee,
Rose, Ann/Anne, etc).