Yes you can

Depends on whom you are with now. If you are with your father then answer is No. And even though if your father is belong from general or other than OBC category then you are in that not in OBC

Yes, since you are living with your mother and she is taking care of you financially too then you can apply on based on her income tax. 

Whether your parents are divorce or living together, you are born to both, hence you have to combine the income of both the parents to prove the annual income of yor family for claiming eligibility for the privilege of OBC NCL category.

The income of both the parents are taken into consideration to decide about the quantum of annual income of your family, hence you cannot conveniently ignore your father's income while furnishing the details of the family income  in the application for OBC NCL certificate to enable your eligibility.

It will be considered as suppression of material facts and an act of fraud which may create more legal consequences to your career.

Your parents income would be considered for determining OBC NL certificate 

you would not be entitled to claim OBC No merely on basis of mother income 

You are not entitled to non creamy layer certificate 

Yes you can

- Since, you are living with your mother after her divorce , then legally you can use the income proof of her for getting OBC NCL certificate as her income is below 8 lakh. 

- 

The caste of the children in India, is basically based on the caste of the biological father. Even if the parents have divorced the biological relationship of the children exists with both parents and children of OBC caste father get the privilege of the caste of their father.

You are not eligible.