BulletProofDiesel makes a replacement EGR cooler for the 05 and up model years. It is a HIGHLY recommended upgrade.
It is not straightforward distinguishing between EGR cooler failures and head gasket failures when a cooling system "over-pressure" has been experienced. IMO you need to remove and pressure test the EGR cooler. If in fact it has not failed, then proceed with head gasket job. Even if it hasn't failed, the BPD EGR cooler upgrade should be done for reliability reasons. Sometimes a cooling system will overpressure if the coolant concentration is very weak (ie way below 50/50). Sometimes the degas bottle will vent because it was overfilled and there was excessive pressure built as the liquid/coolant expanded when it was heated. You need to make sure these things haven't ocurred.
To answer earlier questions:
1, The FICM has 3 voltages. MPower is the 48 volts for the injector spool valve solenoids. LPower is the voltage for the Logic board. It should be close to vehicle power, but it has its own fuse and relay. VPower which is just the vehicle electrical system voltage.
2. Injectors are HIGHLY likely to all be bad. Running out of fuel is a killer to these injectors. In fact, low fuel pressure (below 45 psig) will cause damage fairly quickly.