Nope, there really have been that many coins announced / launched (some announced coins failed to make it to launch, others never intended to).

Pretty much every one that’s been publicised or listed somewhere. New sightings are always welcome.

At least once a month, sometimes more frequently. Expect the frequency to increase further.

Yes and no, in that order.

Because absence of evidence is not evidence of absence. Where a coin is known to be defunct, it is annotated as such. Where a coin is listed on an exchange, it too is annotated as such. The remainder are declared “not known to be defunct”, the strongest statement that can be made, based on the available information.

CC-by, so yes, you may freely use the data commercially.