Eligible for MN1?

[PhillytoManchester]

My American child and I received ILR from SET(M) 5 years ago. I have now British citizenship. I would like register her through MN1 so she has citizenship too, but this doesn't look as straight forward as my process.

My British husband is not her biological parent. I have sole physical and legal custody per court order. Her other siblings are British citizens. She has not been back to the states since moving here.

For ILR, I had to prove why she should settle with one parent in the states. We provided a court order and a letter from her biological father explaining her life is with me and her stepfather. Would this suffice for MN1 too? Thanks!