Single Girl child means that the children is the only girl child of the parents and there is no brother or sisters

You have siblings and are not single girlchild 

It is immaterial whether mother are different 

1. you are not a single girl child

2. sons from other wife are your siblings

Yes, she will be considered as single girl child and legal heirs.

1) for your father's property distribution both wives share will be equal 50-50%.

2) So in this way daughter will get 50% share and both sons will have 25%-25%= 50% share.

You will not be considered as a single girl child.

The sons of your father with his previous wife would be considered as your half brothers as per law, even if your mothers were different as the father of all three is still the same.

Whether the said marriage is legal? She will anyways have share in fathers property.  She will be a single girl child from second wife

It is not clear whether the second wife got married with your father during the existence of his first wife.

If he married after death or divorce of his first wife then children from all sides will inherit his properties in equal share.

If the second marriage was done while the first marriage was not dissolved then the second marriage though is void , the child born out of void marriage can inherit the self acquired property of her father.

There are three children to your father, two sons and one daughter.

What is your doubt about it, she is so far single girl child only to your father.

She is the daughter of your father and your step sister.

Hope this clarifies your doubt

See since there are siblings even from other wife the girl shall not be considered as single girl child.

For both the parents the child should be only the girl.

You are not single child, children's from first wife also your siblings. 

Rights of second wife and child is equivalent to the 1st wife and child gets every right on her fathers property.

Dear Sir,

Single Girl child means that the children is the only girl child of the parents and there is no brother or sisters

Girl is illegitimate child with same inheritance right of sons.

yes she will be considered 

as she is the only child of the natural mother 

Dear client 

That daughter will not be considered as single girl child as she have two brothers and all are from same father. It doesn't matter that they have different mothers.