Had couple of questions related to Non Mehrams

1. For a wife, will her husbands step father become mehram to her and vice versa for husband, will his wife’s step mother become mehram to him.

2. Will the brothers and sisters of step father/mother become mehram to a man/woman

3. After marriage, Will the brother and sisters of step father/mother of a husband become mehram to a wife and vice versa.

by

1- No, for both parts.
2- NO.
3- No.