Yes, tuna is a kosher fish. Canned tuna must be kosher certified though.
It would have to say "Kosher for Passover" on the can.
Fresh water chestnuts are fine. Canned water chestnuts require a kosher for Passover hechsher.
It should be labeled as having had rabbinic supervision for Passover use.
Yes, provided that only kosher ingredients are included in it, and that it's mixed and baked with kosher utensils.
It would have to be certified kosher for Passover.
The label has to say "Kosher for Passover"
Yes, only if they are specifically certified kosher for passover. You can find kosher for Passover olives at any Jewish supermarket
It can be, it would require a valid Passover hechsher.
Yes, it can be since it is made from wine, which can be Kosher for passover if created under appropriate supervision. The bottle would require a kosher for Passover hechsher.
If you were able to find corn vinegar that is certified kosher for Passover, it would be kitniyot which means that the majority of Ashkenazi Jews would not use it.
The number of filets is irrelevant. Tuna when packed in a can is "canned tuna".