Does mopar warranty cover cam lifter issue if engine needed to be replaced?
Yes. From my Mopar ESP:
GASOLINE ENGINE:
Cylinder Block and all Internal Parts; Cylinder Head Assemblies; Timing Case, Timing Chain, Timing Belt,
Gears and Sprockets; Variable Valve Timing Solenoids and Actuators; Harmonic Balancer; Oil Pump, Water Pump and Housing;
Intake and Exhaust Manifolds; Flywheel with Starter Ring Gear; Core Plugs; Valve Covers; Oil Pan; Oil Filter Adapter Housing;
Turbocharger Housing and Internal Parts; Turbocharger Wastegate Actuator; Supercharger; Fuel Injectors (excluding clogged
injectors); Serpentine Belt Tensioner; Seals and Gaskets.
The ESP is only 10 pages long so there's room for interpretation. If you have a stock truck and your lifters go then you're covered. If you have an unlocked PCM/tune, supercharger, etc., then I think the answer will be a definite no (there's a clause for engine modifications).
It will also depend on how hard the dealership pushes back. One of the stipulations is that you have performed the maintenance at the required intervals, especially oil changes that meet the requirements of the Owner's Manual.
There was an article not long ago about a guy's EcoDiesel kicking the bucket and was denied warranty work because he went 18K (or more) before his first oil change. The story focused on that fact but who knows what the whole story is.
I've been to the service department and seen some disgruntled customers. I've been there but, even if you get your way, you've burned that bridge for the future. I'm a middle-aged guy, my truck looks great, and I'm very polite when taking my truck in. I've always gotten great service and, with the exception of one issue, they've been great at addressing the issues. You catch more flies with honey than with vinegar.