Parental consent to gain naturalisation for a child

Hi I live in the UK with my husband and his daughter- they both have indefinite leave. We cannot afford to apply for naturalisation for my husband but we would like my step daughter to apply for British passport which would make it easier for me to travel with her if my husband is not accompanying us.

I see from the form (MN1) that parents have to give consent to apply for citizenship of child . In this case would my husband's consent be enough or does the mother in Africa have to sign too? She has already given official permission for my husband to bring her over here and raise her with me. However I do not yet have guardianship rights although I plan to sort this soon.

So two questions really
1. Do both parents have to give consent for naturalisation of child? Would one parent be enough or one parent +guardian?

2. Can my husband alone appoint me legal guardian using solicitor to draw up papers in UK ar does the mother of my step daughter have to consent to me being guardian too.
There is no problem getting consent from mother as we on very good terms but would like to know what official evidence is needed to confirm her consent. eg official letter drawn up by lawyer in W Africa.

For the purpose of nationality applications, the child cannot apply if the biological parent does not apply or hold british citizenship. Step parents are not considered in these cases.

I am not 100% sure, but a letter/affidavit from her mother should suffice, perhaps a moderator can confirm.

Thanks very much. I will get witnessed letter from her biological mother.

I assume the child was born in Africa?

Could you show that the said child no longer has a connection with the Mother in Africa and does the Father has sole parental responsibility, if so, do you have court documents attesting to that?