Managers take over other managers squads all the time.
Letting a few go and giving contracts to others was probably something that involved more than just Coppell's opinion and were decisions that were taken over the last few months.
It seems a little odd because of the timing, but (if Coppell is leaving) we can't just keep these players holding on until we appoint a new manager as they need to know their future asap to sort out a new club if necessary.