Is there a non-combat version of the cover system, such as leaning back against a wall or hopping up to sit on a box if you're near it?

I hadn't actually thought of that. There were non-cover leans at one point. They looked a little bit naff. You pressed the key and you just went... I know there's plans for sidling, which is like if you've got a narrow corridor, you put your hands up against it and sidle along. So I could see something similar for that: you go up against the wall and just look around or peek around.