I hope that not every stone gargoyle statue is actually alive. It would add some suspense as you'd never know which one is alive and which one is a statue.
I hope that's the case too. I also hope that they aren't like Spriggans and instantly show up every time you enter their territory. It'd be fun to see a gargoyle, sneak up on it, and bash it with a mace for a sneak attack, trying to make it crumble into dust (which could provide rarer drop items than their flesh and blood forms), only to discover it was actually a statue and my follower is secretly thinking I'm an idiot.
Also, it'd be interesting if you could make one a follower if you were a Vampire Lord.