Wedding walk ins

Q: What is the ruling of wedding walk ins in Islam? If I can put it like that. When the reception or walima is held alot of people have their families walk down the isle in the halls, like first the brides's families and then the boys families and the guests all sit around viewing this. Mixed genders. is this permissible? I don't think this conforms to sunnah. Correct me if I am wrong!

Giving money to a student to assist him in his studies for the missed fast and salaah of one's father

Q: Dad was ill in hospital and shortly after he got admitted he passed away. He did not give wasiyat for his missed fast and salaah, so I've taken it upon myself to fulfil some sort of kaffarah (fidyah) on his behalf, and insha'allah Allah will accept.

In terms of spending the kaffarah (fidyah), there is a young baligh male who is from a poor family and needs to sort out his final year of studies in order for him to get his degree/diploma in order to move forward with his life.

Is it possible for me to give him the money or a 3rd party who is currently financially responsible for his payments to pay off his final year of studies?

Car dealership helping the customer acquire a credit facility with interest

Q: Is it permissible to own a car dealership whereby you sell cars to customers borrowing money from the bank and are paying interest?

From my understanding, even to witness the transaction is a sin. In this case we may be encouraging it to make a sale and helping the customer get finance. Is the profit from the sale halaal?

In some instances the banks give the dealers a kickback for arranging the finance with them, would this money be halaal?