It is my understanding that one of the main differences between the Trent engine installation and others is the design of the FOHE and the position it is plumbed on the trent.
Yes. On the Trent, the Fuel passes through the FOHE first when it enters the engine. So there is a chance that any ice could block the passages in the heat exchanger. In the GE the fuel goes through the pumps first, so there is good chance that any ice will be broken up in the pump.