Valid & Invalid transactions

Q: I previously purchased a playstore account with 7 more girls in university. Now I am starting my own android app business so I will buy my own separate playstore account as my intention is to sell features of my urdu learning app. There is some different process to put the app on the playstore for sale. So I want to make a separate test app to test the process of selling.

My question is, can I do this testing on the previously purchased playstore account which is owned by the 7 girls from university and myself. I will only do the testing for the selling process with the permission of the 7 other girls. If yes, do I need to share my profit with those 7 girls when I will be selling my app later on?

Note: I will not put my selling app on this account which is owned by the 7 other girls. I will only test the selling process. 

Q: I am working as a pharmacist in a big hospital. Our market is a generic market where the doctor prescribes the chemical name on the prescription rather than the brand name. The brand is selected by the pharmacist. The same medicine will be sold by different pharmaceutical companies under different brand names but will have the same chemical name. Example, the chemical paracetamol is in brand names like adol, calpol, panadol, tylenol, etc.

My question is that representatives from the pharmaceutical companies come to us and tell us that if we sell their company brand, they will give us some vouchers or a gift. Is taking this gift or voucher from the reps of the pharmaceutical companies allowed in Islam?

Q: A supplier sold fabric to a customer and delivered it to him. The fabric has not been paid for by the customer and it is highly unlikely that the customer is in a position to pay due to his severe financial debts. Do the goods belong to the supplier or customer?

Q: I want to open a business with boating, roller coaster rides, and other similar facilities. Can I provide such entertainment to people for a fee?

Q: I am in the business of buying and selling car mags. A few months back, I sold a set of rims to someone for R1800. A couple of months later, I got a call from the same person asking if I want to buy these same rims back because he had no use for them. I made him an offer of R1200 and purchased them back. Is this considered as riba or is it permissible?

Q: I would like to know the ruling regarding a person who contacts the seller of a property knowing well that someone else is busy negotiating to buy the property. Is it permissible for the second person to approach the seller to offer him more to secure the deal?

Q: When we make purchases online, some companies deliver their goods on cash on delivery terms. But they or a third party (delivering company) charge extra if one pays cash on delivery but no extra charges if we buy using credit card. Is it permissibe to pay the extra charges ?

Q: I live in India. I own a shop. I have to sell it. Can I sell it to a bank or can I give the shop on rent to that bank. Will it he halal for me?

Q: I want to ask if futures trading is halal in Commodity Market. In my country Pakistan, this is allowed. Also, to make it clear this kind of trading has no interest (riba) associated to it. Its a contract to buy the commodity in future by depositing an initial deposit. Please advice. I am a sunni Hanfi.

Q: Is it permissible for a seller to fight with a person for an amount of 1 lac because the purchaser does not want to pay the remaining amount of a property purchased due to some reason. Is this amount halaal for the seller or not?