A new entry into the "most tragic character" sweepstakes....

I think you'd probably hear some thrashing once you climbed up from a very unhappy Gargoyle. Maybe he's just the slacker in the group.

"Hee hee hee.....That guy thinks I'm a statue. I'll just lay low and wait for him to leave. Why they hell should I care about a friggin' bell anyway? Aren't they made to be rang? That's right.....still just a statue. Have your jingle jangle and be on your way."

As far as the condition of the Gargoyles, I think its been implied that other characters have rung the bells before if the path is always the same. One person has been confirmed to have made it to Anor Londo: Iron Tarkus.

Given what he does to the Iron Golem, its not surprising that one of the Gargoyles has been beaten so badly it never recovered. Maybe he just kicked the other one off the roof?

As for who made them, best bet would be Gwyndolin, who can make some pretty convincing illusions...illusions that can totally murder you.