Not prone to cracking.. haven't seen one cracked yet. Not common to leak coolant from head gasket either.
More common would be the coolant side flange at the end of the head leaking... when it leaks, it will run along the parting line of the block/head. I would make sure that isn't your...
Blue wire is very common to break at the connector above the starter motor.
You should have ~12v on the blue wire with they key on. This is the field circuit. Without voltage, your alternator will not charge.
Removing the EGR and cooler will negatively affect warm up times. Especially in cold climates, it's brutal.
The best way to clean the intake manifold is with a torch and compressed air. Or you can use the old screw driver, brush, varsol, messy BS if you want.