Questions on property to be bought using 1031 exchange

[Ramaiyer Ramesh]

I understand there is a time limit of 45 days to identify 3 properties; and 180 days to close. I have few questions on this. 

1) the final replacement property should be from these three ? some where I read that value of the replacement property adhering to 95% rule is important, and not the address of the identified property. 

2) I also read that the replacement property should be closed within 180 days OR the date the Exchanger's tax return is due,  for the taxable year in which the property is sold. Does this mean we need to know ahead of time about this date from QI ? 

3) Typically is this April 15 of next year OR Dec ? 

4) If for whatever reason say I am not able to close on any property, what happens after 180 days ? Do I pay the just capital gains tax (federal + state + depreciation recapture tax) OR are there any fines imposed ?