The necromongers themselves refer to their victims sometimes as "humans", sometimes as belonging to different "races". So, I'd agree that Furyans are just humans from Furya.
I liked the movie, but I didn't *love* it. It had great scenes and moments, but also a lot of boring moments. I heard that Twohy had to dumb down the movie - maybe a director's cut would help? I enjoyed Diesel's performance, though. I think he's fairly underrated as an actor - not that he's a second Olivier, but he can do more than look grumpy, and has a certain charisma that shines even through black googles (watch "Boiler Room" for a very different Diesel).
I'd give it a 6 out of 10.