I very much wonder, what happened to the passengers of those 4 cancelled TK flights. According to civil aviation (international) practice the airline (i.e. THY) is not obliged to provide any accomodation (even F & B) to those pax, except for any transfer passengers. But, I don't know what was done in practice, to provide customer satisfaction. The terminal itself has very little facilities (if at all!) to cater for those possibly 500 pax. The terminal hotel is not opened, the F & B outlets were possibly closed for the day and the seats in the terminal are indeed very very uncomfortable (made of hard ABS/plastic) to sleep on them.
EDIT: Indirectly, I heard that the passengers were bussed (by Havaist vehicles) to different locations in the City and some were given accomodation at the hotels (there may be some transfer pax).