See if any of them come back in the New Year, Ron.
You can always tell them Christmas is too risky to rehome kittens with all the noise, disturbances, absences and hazards like trees, baubles, tinsel and electric wires. That would put the bad owners off without turning away genuine enquiries.
It would also perhaps make them think twice about turning to BumTree for one, which is almost certainly where they'll go next
I was given a kitten when I was four years (1969) old for Christmas. It "ran away".