How much did TK offer you (and your wife + children) to get bumped from the flight?

If you have time, it is not a bad solution.

If you ask for your bags, they will eventually appear at the luggage belts. It may take some time though.

As for rooms, I would expect TK to be flexsible so the parents don't need to stay with 3 kinds in 1 room. Just talk to/explain it to the staff assigning the hotel, presumably at the TK hotel desk in the arrivals hall (after immigration and customs etc.)