They will be turned into cargo planes and unlikely just parked in the desert. SQ and LH are usually smart, we have to bet on UA or somebody to retire their airfleet with us!

Also, LH (which we told it is not) would probably take the seats out and reuse them, so no seats left on the way to desert (if they have to send them to desert and don't find a buyer at all but even the A300s are going to Pakistan & alike)