Thanks for the idea. Results of the simple cup experiment:
2 identical cups, same carefully measured volume of water, placed in same freezer at same time, frozen solid, taken out at same time, holes cut into bottom of 1 cup, both placed into same sink and left to melt at room temperature.
On the left, the cup with the holes. On the right, the cup stewing in its own meltwater. In the second photo, note how much ice was left in the left cup at or shortly after the ice in the right cup was melted. I would estimate at 1/3 - 40% of the ice was left in the cup that was drained.
So now I am inclined to drain the meltwater. Had the results been about the same, I would want to drain the meltwater so that my food wasn't swimming. This experiment makes for a pretty easy call. Thanks again for suggesting it.
Next experiment will be to prepare 2 similar cups, only under conditions of some insulation, i.e. in a coozie, or in a cooler.