No. They still are his children.
no
Up to the limit of child support laws.
No. But, the child/children of the deceased may have a claim to assets of their father's estate.
Can, but the father can challenge it in probate.
Nothing changes regarding child support orders whether it is the mother or the father who is remarrying. The child/children are the responsibility of the biological parents not a new spouse. For example if the mother marries someone of substantial means it would not affect the child support amount that was ordered to be paid by the biological father, as the mother's new spouse has no legal obligation to support the child/children.
The new spouse is not responsible for his/her spouse's children.
No the new spouse is not responsible.
If your brother-in-law is your spouse's brother, then his father is your father-in-law - because he is your spouse's father. If your brother-in-law is your sister's husband, then his father is not your father-in-law.
no
Easy, get a lawyer and aply for spouse visa
A non-biological "father"; essentially, when a woman remarries after her husband's death/divorce, her new spouse is a step father to her children.
Maryland does not have that specific provision, but all child support is rebuttable.