Well, I’ll tell you this- I’ll pray for you.
You seem to be searching for grace, and people who do generally find it.
You aren’t from the “evil side of the family,” I think you might just be God’s answer for your niece to find the buried goodness of her father that us you. Be it for her.
Prayers for your good work in this and the comfort and peace for your niece and the good adoptive parents who are walking through this with her.
Wow...and amen.