I believe Nemesis can override a Lady IF the Mantle wearer cooperates. Maeve was a lousy, rebellious Winter Lady well before Nemesis. The Redcap testified to that.
Yes, she was, I wonder if in the beginning Maeve welcomed Nemesis thinking she could use it to advantage, but in the end it was using her. Unlike Lea, who had a desire for power and thought the Knife would help her gain it. However before it was too late she realized the Knife was using her, confessed to Mab and went for the cure.
Nemesis wouldn’t find such a reception in Molly, especially as Molly is exceptionally talented in this area and proved herself against Corpsetaker. Indeed that battle may have been her successful audition piece for a Ladies Mantle. Lily could still be tricked into submission by Nemesis, and that may have been Mab’s play, Molly to replace Lily. Sarissa wouldn’t, to smart and too tough, Mab still won.
The problem for Lily was she was never the brightest penny in the purse. She was way too trusting and was easily dominated by a stronger personality. Nemesis made it worse, but even without Nemesis I think Maeve would have caused her trouble.