Yes... but not always.
Your brother's wife's mother-in-law can be your mother. Marrying her would be incest, and illegal in most jurisdictions.
Your brother's wife's mother-in-law can also be the mother of the spouses of her brothers and sisters. Those are not related to you.
Well to be honest its up to you whether you want to marry someone related to you
Yes, there was a law passed that slaves could marry with the permission of his master, and they had brothers and sisters. They certainly had friends, especially the city slaves, who had access to their masters and could "put in a good word" for someone trying to gain a favor.
The Law of the Twelve Tables of 450 BC contained a law which forbade marriages between patricians and plebeians. This caused such an uproar that it was repealed and plebeians were allowed to marry patricians again.
There is no law against 2nd cousins getting married.
Who you can marry depends on the laws of the country you live in and the customs of the ethnic group you are part of.
You're wife's brother's wife is your sister-in-law.
brothers can't marry sisters it's against the law, but you can marry your 2nd cousin and down.
Yes, you are only related by marriage. There have been marriages of sisters who marry brothers.
Yes, within limitations of the state law. see link
Mother in-law
Well, you are the brother in law to your wife's brother. There is no real title for your brother to her brother, they can be considered extented family members, though.
Depends in what Country you are. For example , in most of Western part of the World you can NOT. But if you go to the Countries with Islamic law you can do that (Up to 7 wifes).
Probably your niece-in-law.
The brothers of your spouse are your brothers-in-law. Also, the husbands of your sisters are your brothers-in-law.
My wifes brother in law!
It's brothers-in-law.
your father-in-law's house