Can you go buy some flags of 4 different colors?
Mark the Corn in accordance with the emergence.
Green for what emerged first.
Yellow for what came up second.
Orange for what came up third.
Red for what is setting in dry soil.
Report back to us in late summer.

I have experience with replanting Corn.
Basically going in and spotting in areas.
Where the Planter hangs over into an area with a full stand.
The replanted stalks end up being nothing.
Of course, this is a situation where the replant was 4-6 weeks later than the first Planting.