Why does Updike use different character names from different sources in each of the book's three sections?

Gerutha says to her father, "The very qualities that make for public love...may impede love in private." What does she mean?

Why does Gerutha feel so empty? What does she want?

Fengon declares that he believes Geruthe loves him, too. Does she?

Geruthe describes Fengon as "skyey" and herself as "earthy." What does she mean?

Does Geruthe find happiness or an end to feeling empty in her affair with Fengon?

Does Gertrude's marriage to Claudius make her happy?

Does Gertrude know that the King was murdered?

Gertrude makes distinctions throughout the book between what is "natural" and what is not. What does she mean?