Pointing to a lady,a man said,'The son of her only brother is the brother of my wife'. How is the lady related to the man?

In a village of Bastar district in Madhya Pradesh,only two types of people live who belong to a tribal class. The first type is known as class $A$,while the other is known as class $B$. In that village,there is no other type of person except these two. The activities of both types of people are governed by perfectly patterned norms of social behaviour. Each person of the tribe has to obey the norms. They are rigid about this.
As far as marriage is concerned,the following norms are to be followed:
$(A)$ The people of class $A$ cannot marry any other member of their own class,though they can marry members of class $B$.
$(B)$ After being married,each male member ceases to be a member of that class in which he was born but automatically,he becomes the member of the other class to which his wife belongs.
$(C)$ As far as females are concerned,they remain the members of their own class after being married.
$(D)$ On his birth,the child automatically becomes the member of his mother's class.
$(E)$ When any male member becomes a widower or divorcee,then he again belongs to the group in which he was born.
$(F)$ Nobody can marry more than one person according to social laws.
Any class $B$ female can have:
$(P)$ Grandfather born in class $A$
$(Q)$ Grandmother born in class $A$

Lakshmi and Meena are Rohan's wives. Shalini is Meena's step-daughter. How is Lakshmi related to Shalini?

$A$ family consists of six members $P, Q, R, X, Y$ and $Z$. $Q$ is the son of $R$ but $R$ is not the mother of $Q$. $P$ and $R$ are a married couple. $Y$ is the brother of $R$. $X$ is the daughter of $P$. $Z$ is the brother of $P$. Who is the brother-in-law of $R$?

Pointing to a man on the stage,Rita said,"He is the brother of the daughter of the wife of my husband." How is the man on the stage related to Rita?

There are six persons $A, B, C, D, E$ and $F$. $C$ is the sister of $F$. $B$ is the brother of $E$'s husband. $D$ is the father of $A$ and grandfather of $F$. There are two fathers,three brothers and a mother in the group. How many male members are there in the group?