I'm going to answer yes and yes.
V&P is just the new name. So you are Violets and Pearls instead of Diamond sisters. You can either pick to be one or the other, or you can just say this week I'm Arnette's Pearl, and next week, i'm her Violet. Either way.
We dont distinguish big or little.
and yes on the adding to the family, unless polarpi has an objection.