Booking a hotel room for someone who will use it for zina

Q: A person I know does online booking reservation for hotels and rooms for accommodation for 5 star hotels. Some of the clients that approach him are confirmed unmarried adults who want to book rooms for zina purposes. When it is 90% sure that these are unmarried and are booking for unlawful things, if I book the hotel rooms through my website, will it be halaal income or haraam income?

Attending a birthday party

Q: I know birthdays are not halal but if a close person invites me, I need to go. So if I went to a birthday party where there is no music, only relatives and close friends, I will not eat the cake but it seems bad if I don't eat the food they ordered, so if I eat the food will it halal for me? Only to eat the food.

Using someone's credit card and paying back with extra

Q: I live with my parents, and over the past few months, I've made some online purchases using my father's credit card (with his permission). Since there have been quite a few transactions, I’d like to repay him but it would take a bit of time to track every individual purchase. 

Is it permissible if I give my father an amount that is more than the total of my purchases, ensuring I cover the minimum amount I owe him? 

For example, if the purchases total $1000, I would return something like $1200 to cover any uncertainty.