Sea Salt vs Kosher Salt
Bottom line, as in those threads: Kosher is less dense, so you need less of it. Sodium is sodium. Sea salts vary extremely widely in texture, from tiny crystals smaller than table salt to big'uns. Salt to taste.
I don't believe anyone can differentiate among the many salts by taste, other than iodized vs. non-iodized. Added in the same concentration, I find them generally the same, though I keep fleur de sel for its flaky texture to sprinkle atop some dishes.
Because all salt is sodium, one salt is essentially the same as another. Some contain different minerals, in varying degrees, which some people claim to detect in cooked foods. I doubt that. It may be possible to detect variations in flavor when tasting salt, exclusive of anything else, but once it's in solution there's little chance that any difference would be recognizable. That said, if you put raw salt "onto" (as opposed to "Into") foods, I suspect that some difference in taste might be discernible. Kosher salt, any any other salt, can be used interchangeably but, because some salt is fluffed (meaning it contains a greater amount of air per granule than other salts) it's best to make the comparative change using weight rather than volume as a measure of the amount suitable for any given dish.
Yes, there are recipes that specify one salt over another. The reason, if the salt is in solution, is often simply prejudice, personal preference or an attempt to make the recipe appear more sophisticated. If the salt is not in solution, as previously noted, it can be an important aspect of the overall flavor of the dish. But I wouldn't worry about it. For most dishes, if you can detect the salt above the combined flavors of the other ingredients, you've probably used too much salt. (pretzels excepted - of course)