I don’t see where he adopted her, plus the article refers to him as the “Stepfather”, if adopted wouldn’t he be referred to as the “father”?
Also, what about the daughter’s real father, is she in line for inheritance from him that would not be shared with her siblings?
Do not intermingle inheritances into joint property or they become one unless you are fully committed to losing part of it in a divorce.
Never marry a divorced woman with children. Never. You aint the father, you will never be the father, you cant legally discipline them. You will always be just an ATM to them. Stay single or find a woman without children.