You have isolated this as a Spark problem and even narrowed it down to a Spark that does not carry thru from the Dist to the individual wires.

So attack the problem with this narrow focus.

"I tested this by unplugging the coil wire from the distributor cap and holding it up to the negative battery terminal while someone cranked the engine"

An unpugged coil wire sitting on the top of the valve cover should spark...why did you hold it to the neg battery terminal??? Even and unplugged coil wire AT THE COIL, the coil itself will exhibit a pulsed firing that can be heard ---without an assistant.

---When I change my oil and filter I unplug that wire and give the engine a few turns to prime and fill the filter and I can hear the sparks from the drivers seat (yes I know very OCD of me)----

So then... is Why is that Spark, which can be assumed to be going from the coil thru the cloil wire and into the coil terminal at the center of the Distrib Cap and then into the top of the Rotor, NOT making it thru to the 4 Terminals that feed that spark pulse into the individual wires. That sparks path is off the tip of the spining Rotor to the fixed terminals.

Is something amiss with this Spark Path.

If this is indeed the problem then it is one of Timing...the Spark from the Rotor is missing the terminals inside the Distrib Cap and thus NO Spark can get thru to the Plug wire and onto the plugs.

Timing is controlled by the position of the distributor AND/OR the timing belt. On this 88, the last year it could be done, the Timing can be adjusted by turning the distrubutor.

Timing Light and Hand Held Tachometer required.

1st check ...with a timing light or a simple bulb with two probes, does the light go on when the rotor is aligned at the #1 firing position on the distributor.