Permissible and Impermissible employment

Q: I am a student. I teach my aunts son mathematics. This is my first job as a student. I always wanted to earn halaal or I have a wish that my first salary or income will be atleast halaal.

My question is, somehow, I know that my aunts source of income comes from riba or a bank loan or something or fraudness which is haraam. Is my salary halaal or haraam? I am confused. Please explain, if it is not halaal then I will teach him for free. 

Q: My sister recently applied for a tutoring job with good payment online. However, due to being occupied with household chores, she asked me to tutor the kids under her name and profile (without the one who hired knowing) since I am looking for a tutoring online job too. I'm not as qualified as her although I'm qualified enough to tutor those kids but I refused thinking that it would be a deception. Was this act permissible?

Q:

1. Is earning from food delivery (Uber Eats, deliveroo, etc.) halaal, when most of the food delivered is not halaal?

2. What's the ruling on haraam earning in the past which a person didn't have knowledge at the time of earning but when he got to know its haraam he stopped that source of earning? Is the haraam earning in the past permissible to keep, even when he didn't have knowledge of it as haraam?

Q: Is it permissible to have a business that designs invitations for events that are not permissible in Islam, example the business makes invites for birthday parties, engagements, wedding announcements, etc...?

Q: I am a software developer and two weeks ago my friend asked that he has signed a deal with his client for an android app that we need to deliver within 30 days. My friend and his client both are very trusted although the client is a non-Muslim. So what happened is neither he saw the project details nor me and after two week now when I started working on the project I realized that it was a betting app. Me and my friend both are very stressed that should we take the money from this app or not? Since he has transfered the money into our bank account, what should we do?

Q: I work for company called NEXT who’s CEO has political support for Israel.

Also the company provides a credit card for the customers which has interest in it as well. As I work as a sales girl I have to be on the counter/till while on the till sometimes I have to take the credit cards from the customers as their means of payment.

Can you please tell me if my earning is halaal?

Q: Is it permissable for one to collect funds on behalf of doctors from medical aid companies and debtors and charge a fixed percentage to the doctor for your services. 

Q: Is it permissible to work for a clothing store that sells shirts with pictures of animate objects, such as humans and animals? Not all the shirts have these objects but some do. Would the earnings from being a sales associate at such store where one greets customers, puts the clothing on the shelves, works the cash register, etc be halal?

Q: Is it permissible to work as a Finance Manager in a manufacturing company whose financing lines are all from interest based banks and the Finance Manager would have to be leading this activity of arranging loans, managing them and recording them?

Q: Is it permissible for an anaesthetic doctor to work with a plastic surgeon who may do cosmetic surgery i.e a patient is booked for cosmetic surgery and the anaesthetist will be required to put the patient to sleep for the procedure?