How do I get the MySQL binary log coordinates from the binary files?
Hopefully, you did not start mysqld on the slave yet.

It just so happens that a binlog position is also the binlog size at the end of every binlog event. In your case, you can use the last binlog the slave sees, which I can assume is mysql-bin.000006. Get the filesize and use that as the position.

Therefore, on the Slave you would run 

STOP SLAVE;
CHANGE MASTER TO
    MASTER_HOST='...',
    MASTER_PORT=3306,
    MASTER_USER='repluser',
    MASTER_PASSWORD='replpassword',
    MASTER_LOG_FILE='mysql-bin.00006',
    MASTER_LOG_POS=720164815;
START SLAVE;


and that should do it !!!

I have discussed the binlog position being the filesize before


Nov 30, 2012 : How can you monitor if MySQL binlog files get corrupted?
Oct 20, 2011 : How to handle the My SQL DB Master to Master replication when there was a disk space outage


You also asked


  what happens if you set the MASTER_LOG_POS to an earlier point in time? 


Yes, it will replay those binlog event and cause issues.