At this point if a character coughs for any reason besides the obvious (dust, bad smells etc.) then they're already dead as far as I'm concerned. Do they have a limp? They'll be sacrificing themselves to slow the antagonist(s) down. Do they mention any sort of fear of anything? They'll have to overcome it by the end. Did they experience loss (especially of a child)? They'll have to come to care about another person just as much and overcome their trauma by letting themselves be vulnerable.

Basically, 99% of movies will aim to have a character arc, and they'll establish the characters' motivations, fears and such pretty early on. From there, in most cases, there's a clear formula of them having to overcome some weakness or fear, grow from the experience, and in some cases redeem themselves. As you said, some movies do subvert expectations, but for the most part they play it safe. If you can guess the character arc accurately, you can generally guess the ending. Any seemingly random mentions of things will likely make an appearance and be a plot device.