Let's start with one issue at a time as I find time to work on it. First, contrary to your statement, one flood or one even can and does lay down multiple layers of sediment. This has been shown both in the laboratory and in nature. At Mount Saint Helens for example, multiple layers were laid down in both hours and weeks, and significant canyons were formed afterwards. This is documented, eyewitness evidence that multiple layers can occur in just a few weeks from related events.
Also remember that the worldwide flood was a protracted even, with the inundation period lasting 40 days, but as the land surfaces rose and the ocean beds fell, there were countless other geological events taking place over several months and even years. In the case of the ice age, the events of the flood reverberated for hundreds of years.