To replace the coils, all you have to do is disconnect the power source, which is just a plug/receptacle, then remove a small screw. You just pull it up then.
As far as testing which ones are bad, it depends on how bad they are - that is - if they have failed completely or if they misfire intermittently. Hard to find them when they only miss under load, or right at start-up, or just a few times during the day.
The dealers have a diagnostic procedure whereby they locate failures through a piece of equipment called a WDS (Worldwide Diagnostic System). Pretty good at it, too, and charge anywhere from $50.00 to $125.00 depending on location and your PR with them.
$280.00 just for coil replacement is pretty steep. I think you can buy a coil now for $40.00.
Oil pump, huh? Sorry to hear about your troubles. Did you buy the truck new? Do all your oil changes and such?
It was time to replace the COPs recently, I went with the Accel packs from Summit Racing, they came with the wire and boot at $27 each. I was seeing the classic shudder in overdrive at 1700 rpm, no codes, and the packs ohmed out. (I hate static tests on coils)
Easy part to replace, except the last 2 on the passenger side, but even those were not enough to make me say &^$(#j(@
So far about 1500 miles and I'm happy with the performance.