Nightcrawler does not appear to be Catholic or religious in this version.
In the third season, a new original character, X-23 debuted. X-23 was the brainchild of Craig Kyle, Marvel's producer over the show. One day he told the producers and writers about his idea, and asked them to work her into the series. Like many other characters originating in comic book media adaptions, X-23 would later be adapted into the mainstream X-Men comics.
The writers of the show have admitted that they were big Buffy fans. Using Shadowcat as the catalyst, the two shows, Buffy and Evolution, are uncannily similar. A teenage girl with super powers fights bad guys at high school, while she attends classes. Buffy/Shadowcat have opposition against her with first the school principal and then the city mayor. Coincidentally, Joss Whedon, creator of all things Buffy, admits that he is a fan of X-Men, and based the character of Buffy on Shadowcat, even giving her the surname of Shadowcat's team leader: Summers.
The character Spyke is not a part of the comic book based Marvel Universe and was created solely for this show. Unlike X-23, he was never adapted into the comics later on.
Wolverine has two motorcycles. He uses one when he is in uniform (the blue sleek one) and one when he is in his street clothes (the red one).