Out of character- Yes, for the last few years but not for the early years when we first were introduced to Anna.
Hurting Sami- Maybe she’s getting back at Sami for hurting her daughter, Carrie? She’s really hurting her ex- Fauxman too by taking his grandchild but she took his daughter away from him until she was 5 years old before so this could be normal for her.
Money Motive- I’m guessing when her business failed and Tony died, she was left with very little. Anna has always been into money/wealth. She dumped Roman to live the rich life.
Kidnapping a felony- Like many criminals, she doesn’t plan on getting caught. She doesn’t believe they will find her.
Sticking it to Stefano- Stefano has always been about family and spawn so yes, even though EJ is suffering too, she’s still sticking it to Stefano by taking away his grandchild. EJ also knew about Tony being on the island and did nothing to help so I’m sure she doesn’t care if she hurts him too.
She hasn’t seemed her self all the time.