parallax background in both x and y directions?? Plus camera control??

Lokitoes

I don't actually know how to make any kind of parallax background in GS but I've seen a lot of discussion about it on here (but the linked templates seem to have mainly disappeared).

Despite being a complete noob to this area I'm wanting to make something where the character (and camera??) can move in both x and y directions around the scene and have certain background characters go slower to represent distance from the main hero/player viewpoint. So both horizontal and vertical rather than just parallaxing one or the other. Also I currently have my scene set up with my hero controlling a camera that is zoomed in on one small portion of the scene, so that the hero can meet new characters that come into the camera's view as you roam around. Hence I can't use an infinite loop style, and I kinda don't want to have to zoom the camera out to full screen if possible (again, there are clearly some basics about parallaxing that I possibly don't understand). I understand the concept of making characters that are further back simply 'go slower' but this suggests to me that it is them moving and not the camera/hero, so I'm getting confused about how to marry these things together and have character movement based on camera movement and direction.

My idea seems different to using usual parallax scrolling because 1) it's not an infinite looping background, 2) it means the character can go in all 4 directions, not just two, and encounter new actors that are set outside of the camera's view until the main actor moves into their view, 3) it is the camera and character moving around the scene, not the background moving. Is it possible to marry these things together and have a situation where the hero controls the camera and moves around in a small portion of a larger scene, while also having background characters appearing to move slower in relation to the camera??? And have this happen whether the hero is moving in x or y direction?

Currently I have: a scene where the hero controls the camera, limited to a small portion of the scene, so there is more to go around and explore. My background characters move around a bit but of course when the main hero moves the camera, all background characters appear to go by at the same speed - distance from the hero is currently only expressed by the character's size. I currently have x and ys wrapped for some characters who move independently. Hero has simple move rules for left, right, up, down keypress to get them around the scene. Because it is both x and y movement I guess you could say there is a top-down feel to it but because I am using a plain black background with characters dotted around, it is meant to be more representative of a void 3D space with actors who are both closer and further away from the player's viewpoint.

Thanks for any help you can give me... I think I imploded my brain.