Proprietor and its Prop.Firm be regarded as diff. assesee..?

Facts: We deals in wholesae trading business of Readymade garments for Kids wear, girls wear,etc for which we are having only Trade lIcense in name of Firm. Owner or Proprietor is having PAN no. & IT file in name of Owner. Till now no income from such business is shown in personal IT file (which is filled upto A.Y 12-13). Further we are having one Savings bank account in name of owner. Queries: 1. Will prop. and its firm be regarded as different assessee for IT purposes.I think the answer would be NO as Prop.ship business doesn't require registration since there is no registrar as in case of companies. But i am little bid confused as because i'hv read in some forum that Prop. firm will have its seperate PAN No. and will have seperate IT file. so anyone pls clear my confusion..? 2.Whether we can continue to work or transact thru Savings bank account for business transactions or we have to open current account in name of firm...? 3.Wht are other legal compliances or registration that i need to obtain to act as a prop.ship business.For example, for VAT compliances, when to regiser for VAT & CST License under WB VAT Act. Whether opting composition scheme also requires VAT registration..? 4.Also I want to amend my name of firm as published in Trade license. can i able to do so and how..? 5. Can anyone guide me via step by step procedure to revive IT file and how to incorporate business income in my personal IT file if business doesn't requires seperate IT file. 6. Since we are small trader having small turnover around 3-4 lacs a year, we havn't maintained accounts of business transactions, so in such a case how it wud be possible to incorporate in past years income for income tax purpose. Also for future whether we are required to maintain books of accounts..? 4. As mentioned above in facts,ITR is filled upto A.Y 12-13, I think for A.Y 13-14 time is gone for belated return also i.e. 31.03.2015. Is there any other possiblity to file return incorporating business transactions for A.Y 13-14. If No then what would happen or that year. whether this default wud destroy the worth or value of file in obtaining any kind of loan. 5. Few more basics queries are there but dependent on above answers. Thanking in advance.