Is Isabel Archer a moral being? Is anyone in The Portrait of a Lady?

Madame Merle has been very cool to Isabel. Merle has accomplished her goal - she got Isabel to marry her friend and protege, Osmond. Now, years later, as the marriage is clearly a disaster (at least for Isabel), Merle is nowhere to be found - until she has another need - this time more difficult to fathom. For some reason Merle has become the champion of the relatively poor (relative at least to the super-rich, idle Americans who populate "The Portrait of a Lady" and almost all Henry James novels) Rosier as the suitor for Isabel's stepdaughter, Pansy. Why does Merle do this? It clearly sets her in opposition to the wealthy suitor, Lord Warburton. I can't see what's in this for Merle. I can see that it will force Isabel to make a decision - should she advocate for Rosier (a marriage of love) or for Warburton (a marriage of convenience, much like hers). Obviously there's no choice at all from a moral point of view. But is Isabel a moral being? Is anyone in this novel? Isabel may have started as a moral being when she arrived in England, but her exposure to the European class culture and, even worse, her sudden and unexpected inheritance that changed her social status (like winning the lottery today) has apparently upended her moral compass. She's as bad as any of them. But she will face this one final test. Friend Bill who has recommended Portrait to me for many years, described it to me as a novel in which the characters are faced with a huge moral and ethical decision. I don't know how high the stake are here - the decision will affect no one outside of this tiny, tight knot of privileged and self-centered characters - and we travel an awfully long way with them beore they (or Isabel) confront this decision, but there still is something compelling about James - the acuity, the high intelligence, the sense that narrow as his world is he knows it intimately.