Species is most easily defined in extant sexual populations, since you can observe reproductive compatibility. Two populations that cannot or will not breed are considered separate species. Just in the last few months I've noticed that most creationists have punted on claiming that this does not occur, quietly moving the goalpost for macroevolution to the genus level.
In asexual species, you have molecular and anatomical evidence, but it's not so clear as for sexuals. For fossil species, all you have to go on are anatomical clues. That's fuzzier yet. You can picture future paleontologists arguing over St. Bernard and chihuahua skeletons.
LOL
I know you did not mean to imply this, but the first thing I thought was, "This means that homosexuals are a separate species."
That WHAT does not occur? Reproductive compatibility?
Yours is the classic definition of "species." That answers #3 above. On this, there is no dispute.
That's not evolution, that's not even speciation. A human in Los Angeles cannot breed with a human in New York City, but that does not mean that they are different species. You make up such nonsense because you know your theory cannot give proof of a species ever transforming itself into a new, more complex organism.