You have to know the dietary laws and act in accordance to them.
It should have kosher-certification.
As with most products, grape products require kosher certification. If they do not have proper certification, they should not be considered Kosher.
Anything that has a kosher certification on it.
It's a kosher certification agency.
It can be, check the package for kosher certification.
It needs to be cooked in a kosher vessel and have kosher ingredients. If purchased, it (or the bakery) should have kosher-certification.
The answer is that it really depends on if the product has a kosher certification, or not.
Capers can be kosher, they require a valid kashrut hechsher (symbol of kosher certification).
It can be. You'd have to check the packaging for kosher certification.
There are kosher brands of l-taurine supplements. You would have to check the packaging for kosher certification.
Yes, it is kosher dairy (not chalav yisrael)
It can be. Check the package for a kosher certification symbol.