[Wombii]

The only compartments that are actually articulated are the lower rear switch boxes as seen at the bottom of post #2 and #44. I made a reasonably scale accurate but simple hinge with styrene and 2mm brass tube. Keeping them closed was an issue. Friction fit is an option, but in the end I went with tiny magnets and an M2 metal washer in a corner of the door.
The lower side plates (and the rear wheel arches) for the center/tank module are long plates attached with cube magnets. I suggest 1 cube magnet + 1 screw per corner, as that makes it adjustable.
The shutter doors for the front/pump module are pretty much plastic sheets attached with cube magnets in a way that lets me push the top to flip up the bottom (small piece of plastic tube in the middle to force the plate to rotate around the center).
The Rear shutters are not designed to open, but they are slotted in so they're removable after taking off the rear module for maintenance.
You might find that the magnets are strong enough to crack the glue and snap off if you let them slap together, so something softer than CA glue is advised.

edit: I'm using 4 or 5mm neodymium cube magnets. They're very strong, small enough to fit and large enough to not lose track of them. I'd love to use smaller cubes, but the thought of handling those tiny things without losing a couple in my eye or something honestly scares me. There's also an issue of pets or kids accidentally eating them if they fall off. I also have a variety of small neodymium disc magnets for other places like the interior ceiling.