The girl's mother had said her family had a Christian heritage but foster carers were Muslim.
Bosses at Tower Hamlets Council say an investigation by one of their senior social workers shows that a number of complaints were unfair.
They say the investigation shows that foster carers provided "warm and appropriate" care to the little girl - although they said findings were disputed by the youngster's mother.
The case, which is being overseen by a judge at the East London Family Court, hit the headlines more than two months ago.
Judge Khatun Sapnara decided in late August the little girl should move from a foster placement to her grandmother's home temporarily, pending further analysis of evidence.
She has said the little girl cannot be identified.
Social services staff had assessed the grandmother as a suitable long-term carer, said the judge.
The girl's mother wanted to ''resume the care of her daughter'' as soon as possible, she added.
On Wednesday a Tower Hamlets Council spokesman said in a statement: "Although the mother disputes the findings, the local authority is satisfied that at all times the foster carers provided warm and appropriate care to the child.
"The local authority has been impressed with the care and commitment shown by the carers to the child."
He added: "The local authority does not accept the allegations as made in the national press."