Like trygirl, I suspected that Vielandt was still around when the dates on the painting were after his death. I didn't know whom he was until the Comte asked Miss Temple how she felt about art. I felt Dahlquist was telling the readers who he was then and I was surprised Miss Temple didn't pick up on it, as she was so quick to solve other aspects of the cabal. When Francis Xonck called him Oscar it was to dispel the suspense of anyone that didn't catch the first hint.
As for the Contessa, I felt that the Comtes' familiarity with other women, prostitutes, and some of the erotic aspects saved in the glass must have been behind much of the Countess's hatred and need for power of her own, separate from his. I didn't really think she survived until it became clear that that others landed so close to land and then it occurred to me she might have jumped close to land too. That she is a worthy villain for the next book is true. I was hoping that Francis Xonck survived because he seemed the only virile and worthy opponent to challenge Chang. (Besides the Contessa)
"If there are no dogs in Heaven, then when I die I want to go where they went." Will Rogers
Growing old is mandatory, growing up is optional.