No, it doesn't matter whether shellfish and pork are real or fake - they can't be kosher.
There are brands of kosher imitation crab meat. You would have to check the product packaging for kashrut certification.
Only if NOT made in a factory that also produces shellfish products. Some packages say that this product is made in a factory that produces peanut, and shellfish products. Shellfish are not kosher, that means not a food. Read the warning on the package. You can find "kosher" brands. I found them mostly online in kosher stores.
Whey is a dairy product, made from milk and can be kosher. As this is a processed food product, it would require kosher certification to be considered kosher.
A scallop would be considered a shellfish, not a potato.
Real teriyaki sauce, which contains soy sauce, would be kitniyot. There are imitation teriyaki sauces available for Passover.
All plants are considered kosher. They need to be washed thoroughly, (especially leafy vegetables,) to make sure there are no insects on them which would render them non-kosher.
In Judaism, foods that are considered non-kosher (treif) are banned. These include pork, shellfish, and any mixtures of meat and dairy products. Additionally, any food that has not been prepared according to Jewish dietary laws (kashrut) would also be prohibited.
Whether of not a specific hydrolyzed gelatin is Kosher or not depends on which animal it is sourced from. It is an animal product. The container/bottle it comes in would be required to display a Kosher certification symbol to be considered kosher. Otherwise it is automatically assumed it is treyf or non-kosher.
Certainly! What do you think people drank before modern plumbing?
Yes. Keeping kosher is far healthier. For example, shellfish which are forbidden, eat all the garbage of the sea, and are pretty contaminated. Also G-OD forbid all animals that there hooves aren't split, and it turns out that the split hooves let out a lot of toxins, that you would have ate, had it been a non-kosher animal.
Corals would be an example of stationary animals. Many shellfish could be considered stationary in the short term, but they will move.
It would be kosher if it came from a kosher animal.