Self occupied and vacant property

I took a loan of Rs 30 Lakh from a bank and Rs 12 Lakh from a Co-Op Society, and  purchased a flat, which is now vacant for whole year as I could not find desired tenant. I residing in our ancestral house in the same city. My query is, as my flat is vacant, can I claim the the grand total of Interest i.e the Interest from Bank + the interest from Co-OP Soc + Pre construction Interest for deduction under Sec 24- which rises well above Rs 2 Lakh .Pls explain the calculations in detail.

If I wish to sell that flat now then which date will be considered as date of puchase, i.e date of registry or date of occupation.
(Date of occupation is earlier than the registry)