1. That would salt all the land with the evaporated sea water, causing hostile growing conditions.
As sea level dropped, the saline water would have run off, then the fresh water came into contact with the cratonic surface, where it too ran off (save the part that filled up the lakes). The only water left to evaporate on the continents was fresh.
2. Not all around the world... Fish don't move as fast as you think.
They wouldn't have to move very fast, just fast enough to keep up with a rising sea.
3. Why is there no geological record of the flood. The corrosion and mineral deposited would be obvious.
Corrosion of what, by what? What type of mineral deposits would you expect to see? Where? Why?
4. What about all the plants? They can't survive underwater.
They need not. The plants on earth were being consumed by herbivores. This means that the seeds of the plants were in the guts of the animals that died in the flood. When animals die, they often fill with gas, which makes them float. All that would be necessary for the seeds to survive is for the decomposition of the animal's carcass to take longer than the duration of the flood event. The plants grow from the ingested seeds where the animals were deposited after the flood.
5. What about deserts, the sand would be carried away, leaving unexplained sand deposits and huge craters.
Why would there be craters? Are there craters in deserts today? When the sand was 'carried away', it had to be deposited somewhere, right? Those would be the sand dunes of today.
PS~ I live in the desert, and desert's are far more than just sand dunes. If you would like to discuss the desert environment, I'd be happy to do that. The only thing you've addressed here is ergs.
6. What about all the ruined topsoil?
There wasn't any ruined topsoil. As sea level rose, the fresh water at the top of the water column came into contact with continental soils first, such that the soils were saturated with fresh water. Once the flood receded, the fresh water in the soil was evacuated via evaporation and capillary forces, providing a well-preserved, dry soil profile.
It's a silly story. ^I just thought of those off the top of my head.
Luckily none of these 'issues' that you've pointed out are actually a problem. YAY!