1) Significant quantities of ice accumulate in the centre tank.
Syeng, problem with number one there. Centre tank is the warmest tank, so significant quantities of ice are unlikely to accumulate there. The reason fuel temp is measured in the wing tanks is because that is where your coldest fuel will be. Also, centre tank is emptied first, so fuel spends less time in there to cool down. It is very rare to be planning to land with fuel in the centre tank, so you're not going to get buildup of ice over multiple legs.