I get nervous when I see visual signs of carbonation in the bottle. In my experience, that means IED. Whenever I see signs like you've described, I immediately open one just to make sure all hell isn't breaking loose.
Yes, you should see a light lees layer in the bottom. And a krausen isn't out of the question either. But your question is pretty generic, if you follow directions and do what you're told, you don't have to worry about it.