Margie, except for color, those irises look similar enough to me to be
sibs. With one "pink" parent, seems reasonable to me to get this range
of color from the same pollen parent.
Of course similarity is hard to judge from the photos - is the
difference in color what makes you suspect different parents.
Any reason to think there isn't pink or yellow lurking in LADY CELESTA,
hidden by dominant white?
trying to get used to having soil moisture in the summer again! My
house has been eaten by jungle, not to mention the irises.