Permissible and impermissible items of trade

Designing a structure for a church and selling grapes to someone who will use it to make wine

Q:

1. Is it permissible for an engineer to design the structure (i.e. steel in beams, columns, etc.) of a building which the owners will use for producing alcohol?

2. Is it permissible for an engineer to design the structure of a church?

3. Is it permissible to sell grapes to someone who will use it for making wine?

Purchasing products that have a cross

Q: As we have to buy products like sunscreens and medicine even from the non Muslims (if the ingredients are halaal), they sometimes put crosses on the packaging.For instance, a sunscreen package may have a cross, the same goes for some medicines or patches.

Is it considered haraam for us to buy such medicine or sunscreens if the packaging has a cross? 

Working in a business that sells traditional muti products

Q: At work, I'm one of the buyer's for the cash 'n carry. They sell these traditional muti products amongst many other cosmetics, sweets, household items. These traditional muti products like tokoloshe salts, oils, etc. have phrases such as "win the lotto", "bring back lost love", "go away evil", etc. on its packaging. Now I have to buy these products, price it, promote it and so on, amongst other items. I really feel uneasy about it as its wrong and impermissible to sell according to my weak understanding. I don't know how to approach the boss and inform him. And the more heartbreaking thing is that one of the biggest suppliers of these products is Muslim owned, and also many of our Muslim brothers have specialized shops selling these products. What should I do and is my earnings doubtful or haraam?

Selling women's clothes online

Q: I am doing business online. I sell portraits and paintings, etc. I also sell hand painted hijaabs and sharee gowns. I like to wear beautiful clothes at home. From here I feel a hijaabi sister can wear attractive clothing when they are at home in front of maharams.

1. Am I in a trap of shaitan if I think this way?

2. Can I sell these clothes to non hijaabi sisters?

3. Is it permissible to do this type of business?

4. I know that niqaab is a permissible dress code in islam, but there are many controversies about hijaab. Can I sell hijaab?