Taking an interest bearing loan to start a business

Q: I want to start the business with my friend. We live in India. I want to have clarification with following points

1. Can I start a business by taking loan based on interest?

2. If above thing is not possible then is it OK if my partners take loan and I restrain from it?

3. Is it ok if I work in their (my partners firm) which takes loans and take my share of profit as employee?

I wanted to have clarification because in any way the firm in which I am working currently has taken loan from banks for its functioning.

Hair dye

Q: I wanted to color my hair to brown, is it permissible to do so? I read on islamqa.info that it is permissible, but is it really the case?

Adoption

Q: Is it permissible for someone to give away his newborn to his brother or sister if they don't possess a child and the child is to to be adopted forever.