P0302 is Misfire Detected in Cylinder 2. If it is the 4.0 inline 6, this will be the second cylinder from the front. I do not know off the top of my head which is cylinder number 2 for the 4.7 V8.
That is a fan relay error. Recommend replacing the relay, these jeeps are notorious for burning them up.
.035
There is no such thing as a 2002 Cherokee Laredo. The last year for the Cherokee was 2001, and the last year it came with the Laredo trim was 1992. I have a 2003 Cherokee Laredo so this awnser makes no sense at all. Do you have a GRAND Cherokee Laredo? Those are still being made. They are not the same as the Cherokee.
NoNo
You have a leak that needs repaired.
No, they are not interchangeable.
It has a timing chain.
It can not be removed and have the engine still run.
Yes, some will be.
No. They are not interchangeable.
The water pump is on the front center of the engine.
No, you will need to remove the tank.