well, a squeak/creak could begin to sound like a rattle. And a rattle could have some components of a squeak. And a component that is supposed to have some give/flex cause a squeak and rattle.
But, by all means, if you find someone loose that shouldn't be, tighten it down.
As for other possibilities of "rattles" coming from the hatch area: check the plastic push in pins connecting the bumper to the rest of the car. Those tend to relax their grip over time/rough roads and may cause a rattling sound from the back.
But, i guarantee, those plastic/rubber bits will begin to dry sooner or later and you should apply silicon grease to them to prolong its life and mitigate unwanted noises.