Considering it came from Enterprise, I'd be guessing that its a human nickname that stuck... kind of like the 'bird of prey' ... K'Vort and Br'el different ship classes that bear a resemblance... This Raptor seems to be the same size and configuration with new technology... don't see any difference in the class title of the original Excelsior versus the Excelsior class ships used in the Dominion War... different technology, same layout, same class name. The Federation sets precedent for using old ship classes with new tech making it seem within canon.
The K'tinga model was used for a bunch of different Klingon ships (and even Romulan ones). The D5s and D7s look like the K'tinga, but they all have different names.
To me calling a modem ship the name of a ship that's 200 years old is like making a new SUV with a hydrogen engine in it and calling it a Model T Ford. This ship isn't the Raptor (yes, it's Raptor based). It should have a new name (even if it's Raptor cha')