A 12 inch coilover will give you around 3 inches of up travel with a 4 inch lift. Unless you are running uncomfortably stiff strings, your bumpstops are gonna get a workout.
With EVO Rockstars and long travel upper mounts, the shock body is still dangerously low. Low enough that the right rock is gonna do serious damage.
Only way 12's work is with a long travel upper mount and standard lower mounts. With a 4 inch lift, you'll have roughly 5 inches of up travel. That's reasonably workable.
I agree with the other comments on valving. They are gonna be way the fuck off. Raptors are valved for fast desert travel. JK's, aside from DTD equipped JK's, are not.
For around $600 you can buy properly valved, 12 inch King remote reservoir smoothies, hell, I've got a set in the garage I'll sell for that price. That's a much better option than experimenting with Raptor valved shocks.
They'll still be too big however.