I know people render multiple images and then put them together. But is there a way to make sure the angles and all will be correct so one thing doesn't end up out of place?
In Poser you save the camera angle so you can reapply it later in a new scene.
I am sure there is a way to do the same in Studio.
also lock the camera in place so you can't accidently move it
I usually create and save the Camera and lights as their own files (Save Camera Preset and Save Light Preset, respectively) then merge them in to the scene(s) when everything else is set up and render through that camera only (I usually name it ShotCam to remind me that it's the camera I want to use)
Fair warning, I'm using DS Pro 18.104.22.168, so things may be slightly different if you're using DS 4.5 with the DUF format, though I imagine that there should still be options to save just the cameras and lights.