The 18:15 would be EY408. The last few times I have used this flight it has been delayed by between about an hour. This would make things more difficult for you.
Checkout the recent history of 408. Its not very good:
http://www.flightradar24.com/data/flights/ey408/
Why not take the Air Berlin connection from AUH to HKT? That would be much less hassle at the beginning of a holiday