Your wife's sister is your sister-in-law. You are her brother-in-law.
Your sister in law is your husband's sister or your brother's wife.
Yes
Yes.
Probably your niece-in-law.
Your uncle would be your sons great uncle. Normally your Son would also call him 'Uncle .... '
You're wife's brother's wife is your sister-in-law.
Yes. You can marry your LIVE wife's sister if you want to, provided that you are both free to marry.
My wifes brother in law!
There is no specific word for the husband of your wife's sister. If you need a phrase, call him your "sister-in-law's husband."
M Shadows wifes sister Michelle Dibendetto
Heracles' wife was Deianeira, daughter of Dionysos and Althaia, and sister of Meleagros.
You would call your wife's elder brother's wife "sister-in-law."