I love
Iris, and would have used it if our second had been a girl. I love all three meanings - rainbow, flower, and body part. I think the association with the eye is wonderful. The eyes are the window to the soul and the colored part is called
Iris because it comes in a beautiful array of colors and patterns. So that's only a plus for me.
I prefer the spunky sound of
Iris over bland
Lily or cutesy
Poppy. I like
Rose alright though.
Having the same initials is not a big deal.
Iris Arabella is lovely. My favorite combo is
Iris Josephine.