Probably too lean to promote the first start when cold. Cranking to "check spark" without the engine being able to fire (because the coil wire is disconnected) introduces a fuel charge because the injectors are firing during the "spark check". When you reconnect the spark, the prime charge allows the engine to fire.
Low battery voltage during cranking can also inhibit fueling (injectors won't inject as much volume if voltage is low), and cranking speed. Sometimes system voltage affects fuel pumps.
I would be suspicious of injector flow rates,. You have the means and equipment to check them. In the meantime, sometimes blipping the starter a few times without trying to start it builds fuel pressure, and pulses the injectors to prime it. Then hit the starter for real to start it.
Another way to identify "too lean to start" as the culprit is to disconnect the ECT sensor at the front of the intake. This defaults the ECM to full rich enable. If it now fires, go back to injector flow, cranking speed / system voltage while cranking, fuel pump voltage.
