Just some thoughts, so take them as you will.
Kudos for getting your son involved.
For a random misfire, I would check the crank position sensor and the gap. Sometimes crud can get built up down there, the bolt that mounts it gets a little loose, or the sensor is heading south. It may also be as simple as a loose or corroded connection. I remember there was a TSB on the '97s about this, but don't remember the details. Maybe you can find out more about it online?
As for the oil on the spark plug, was it on the electrode side or the porcelain side? If on the porcelain, it's a leaky valve cover gasket. On the electrode side it's a sign of something possibly more serious.
A compression test will tell you the health of your engine, but it won't tell you where the compression is siphoning off at. For that, you need to do a leak down test.