So the "bug" thing...I don't know if this is maybe regional, or maybe just coincidence but in my extended family plenty of parents call their children "bug" sporadically. It's not a nickname, not in the sense that usually a nickname is something multiple people call one person. It's more a term of endearment, equivalent to "hun" or "sweetie". (See also: "doodlebug", "cuddlebug", "lovebug") I guess I thought it was more common than it must be. But I never interpreted it as any sort of specific comment on Kate or anything really particular to Kate, not any moreso than if Rebecca called her "pumpkin".