Permissible and impermissible items of trade

Q: Is it permissible to sell the testicles of halaal animals?

Q: I am interested in purchasing a company that manufactures malic acid. The acid is used in the manufacture of sweets to make them taste sour and also used in the manufacture of beer to give it a sour taste. 

The main customer base of the company is the breweries. 

Will it be permissible for me to purchase the company and maintain the same customer base?

Q: Is it permissible to sell zamzam?

Q: Is it permissible to sell rolling paper usually used for weed often known as rizla. And selling lighters to someone you know will used it for smoking?

Q: I have noticed that my father has been selling filter/rolling paper (rizla) in bulk such as in large boxes to possible retail customers. I would just like to know whether it is permissible to sell such an item given the nature of its use?

Q: I would like to know what is the masaail concerning fake goods. As a retailer stocking original goods (which does come with its price tag) finds others selling fake goods matching the originals at a much lower rate. Is it permissible to stock these goods? 

And what is the masaail concerning a person purchasing fake goods because the price is right.

Q: 

1. Are we allowed to manufacture coffin boxes? 

2. Are we allowed to sell coffin boxes?

Q: If a person owned a leather jacket and found out it was made from pig skin, can that jacket be sold to a non-Muslim and the funds be used to purchase another item?

Q: Is it permissible to sell collectable cards, such as soccer cards, Pokémon, etc. Also video games disks, etc.