1031 Exchange Panic, looking for quick help

[Sharon Whipkey]

We want to identify 8 properties. 

1. If one property falls through is the whole exchange lost or just the one property's value gets subtracted from total value of property accumulated and liable for capital gains tax?

2.  If one property fails to close escrow, can I apply what would qualify as down payment to another property with an open escrow?

3. With the 200% rule, can I identify more properties, than I ultimately buy or once identified do I have to buy all identified properties.

Search extensively on line, all information vague.  Read BiggerPockets Brandon blog, doesn't address issue.  ]

Thanks for assistance