Sounds to me like you might have had a leak somewhere in the lid. As far as how that looks, pretty normal to me. That ring of gunk is typical after fermentation, and no krausen is typical as well. 4 days to go from 1.046 to 1.008 isn't out of the question either, depending on your process (pitching rate, fermentation temperature, aeration, etc). What does it taste like? After putting the lid on, gently push on it and see if your airlock bubbles. If it doesn't then there's your leak, but you might still have a small/slow leak even if it does bubble when you press on it.