To me it felt like Carlisle thinks he has become even more devine he was "givein" tools to better help humanity he strongly rooted in his religin maybe even more so then before he was a vampire. Its also good he doen't PUSH his beliefs on everyone but lets eveyone know what he belives.
Edward cristian or cathlic usta be before the change the whole atoning for sins and after believes nothing's beyound for him, but it doesn't make him a bad person,(well maybe during his reblious time
), but personality wize he's always been the same.
As for the rest Esme,Emmett,Roselie,Jasper an maybe Alice seems like they would have been more like me only went to church because you was made to by your parants and back in their time would have been bad gossiping if someone didnt go to a church. They are all have good morols (when the veggy part started maybe not so much when they was human blood suckin)
To me you dont HAVE to belive in certain beliefs/religen to be a good morol person, (I dont think if i do this or dont do this am i goin to Heaven or Hadies mine is more what whould "someone"(family, friends) think about me noone wants anyone close them to be hurt by or think bad about you. (If ya go to Hadies for not believing well I guess ill be in the pits of tartous)
In the book getting hurt by cross, holy water is all Myth then why didnt they contiu to go to their churchs after they got good in their veggystate? I know humans subcon..stayed away from them but there is backrows, Was they afraid that would be one Myth that wasn't myth?, walk in an turn to ashes. It seems to me Carlisle would have found himself a church an Esme would have went with him maybe even Alice.