As per my understanding as the questions above in my opinion
1. Since the flats are ready for sale before then GST will not be applicable. As per the provisions of the GST, if the construction is completed and we have received completion certificate then this would not be covered under GST.
2. where tax was paid on any supply, both under VAt laws and Service Tax laws, TAX SHALL BE LEVIABLE UNDER GST ACT and the taxable person shall be entitled to take credit of vat or service tax paid under existing law TO THE EXTENT OF SUPPLIES made after the appointed day ie 01/07/2017.
This means the proportion of the supplies made after 01/07/2017, we will get the proportionate amount of credit.
3. If the builder is covered under composition scheme then point no 2 is relevant.
if builder is not covered under composition under the vat laws then he will be eligible for the input credit.
Important Conditions are as follows :
a) credit should have been allowed in the VAT laws. If credit was not allowed under vat then if would not be allowed in GST also.
b) Credit is allowed under the GST. If the input was allowed under Vat but are not allowed in GST then no credit would be allowed.
c) The tax have been paid on the inputs buy the suppliers
d) Returns have been timely filed.