Annabelle says that she knows exactly how everything turns out and that there are no surprises in Heaven. So, why didn't she know Charlie was going to rewind his watch? Because Charlie's not like other animals who get into Heaven: he'll take the difficulty of living over the easy way of the afterlife. Charlie is a surprise. At the end of his song, he even sings it:
Annabelle: What's that you have behind your back?
Charlie: She's gonna be...
Annabelle: Charlie, don't wind that watch!
Did they imply at the very end that Charlie managed to break out of Hell too? Theoretically the Satan dragon could be in the town merely to retrieve him, but since we don't see Satan running about to pick up the many people that go to Hell, Charlie must have done something to piss him off.
No. He'd already BEEN to hell - after his watch died. Satan was there to make sure he returned after his little visit, but Annabelle intervened and saved him.
Well, that still leaves the question of how he got the chance to go see Anne Marie before Annabelle showed up. If he broke out and escaped back to Earth and Satan showed up to drag him back, that's kind of awesome. If he managed to con/bargain his way into one last visit and Satan was just there to ensure he returned afterwards, that's still a kind of awesome moment for Charlie. Either way, that's fairly impressive.
During the beginning of "Let Me be Surprised", in the background, a lion and a lamb can be seen snuggling together, snoozing peacefully... a clever reference to Biblical passages describing Heaven as a paradise where "the lion will lay with the lamb."
It could also be that when she says "we know everything", she's referring to everything in Charlie's life...the one that just ended. Although it could just be that she hadn't bothered to check past Charlie's death in the book when she greeted him...why would she have needed to?
It's possible she didn't mean omnipotence, but that dogs were just predictable.
Annabelle was also increasingly conveyed as pompous and infallible as well, needing Charlie to protect heaven from one of the angels she entrusted. Saying she knows everything just seems akin to her character.
Not counting the series, the reason Carface isn't in hell during the Christmas Special? After having to endure him for a time, Satan kicked Carface out of hell and restored his life becuase he got so annoyed with having him around. Now let that sink in for a moment...
Also following that logic, Itchy came back to the land of the living becuase he missed his pal so much awwww.
Alternatively, perhaps Red handed Carface over to Belladonna, who released him to ensure his loyalty?
Red is a cat, and if hell is akin to the cartoon's canon of heaven, cats likely don't keep charge of doggy hell. And if Belladonna is Annabelle's Evil Counterpart, she likely had rightful charge over Carface. And with Annabelle sending two guardian angels around to help the living, why wouldn't she fight fire with fire?
In the Christmas Special, puppies are seen in Heaven. That carries a rather sad subtext.
At the end of the Christmas Special, Carface says he's going to visit his mom. Assuming this is the same Carface from the first movie and not a reincartion his mother is long dead by then, meaning he would be visiting her grave.
If memory serves, the movie implies that she's either died (Careface's tearful, "Mom, I miss you.") or is very old by that point, it's never made certain which happened to her, so she could still be alive by that point.
The only way to kill Charlie is by stopping his watch. This is shown during the ray gun scene. Now, imagine if King Gator had succeeded in eating Charlie. The poor dog would have his flesh and organs melted in the gator's stomach and he'd end up being digested...and he'd still be alive during all this.
He was a rotting corpse with a broken back when he first came back until the watch started ticking at which point he returned to his normal living body. Which makes it likely that his body would regenerate if hit by something. Of course this still leaves the horrible possibilities of him feeling "everything" like Wolverine.
Itchy's death by chicken bone in the sequel. Sure, he and Charlie are together again, but poor Anne Marie has now lost two of her dog friends (and probably quite close together, since Itchy doesn't look much older when he shows up in Heaven). Worse, Itchy died after she promised Charlie, who gave his life for her, that she would take care of him. Imagine how much grief and guilt she must be dealing with...
King Gator is not just gigantic, he's genuinely obese. He's eaten so many helpless victims that he got obese from it...