I haven't yet disassembled my mask yet but looking at the interior, I
think the inner grey shell is screwed into the outer green shell with a bunch of screws, and the mouth screen and lenses are sandwiched between. There's definitely an extra black frame on the interior around the lens part, but I'm not sure if this is for comfort/wear or is part of the mechanism holding in the lenses. (gotta love the OSCORP logo stamped inside!)
I will say that the gold covering in the lenses is likely incredibly fragile so take a lot of care when disassembling and re-assembling. Masking the lenses runs a risk of damaging that coating.
As for the pumpkin bomb, removing the four screws around the battery compartment detaches the lower copper ring and allows the lower set of copper "ribs" to be removed, in four parts.
Theres an additional three screws that appear to hold the two halves of the inner green sphere together. Removing those
should allow the bottom half of the sphere to be removed... except the top set of copper ribs are locked into the bottom half of the green sphere with plastic clips and seem to be holding it in place even with the screws removed. I can't see any easy way to remove those ribs without snapping either them or the plastic inserts holding them in place. I'm reasonably certain there's no glue involved, it's just the order of operations to assemble the parts doesn't really work in reverse to allow for it to be disassembled. Maybe someone with better coordination than me can figure it out.
Removing the lower ribs should make it easier to paint them and mask off all the green parts and paint the other copper parts.
I really wish I could remove the inner electronics/core because I want to insert some diffusing material under the end/cap button. The single LED there is really noticeable and needs something to diffuse it. I put some 2mm packing foam/fabric under the bottom end cap and it helped to diffuse the two LED's there quite a bit - it just needs some slightlythicker material - maybe some aquarium filter floss...
I would love to find a way to do the same with the top LED, but short of snapping the ribs off and re-gluing them later, I can;t see any easy way to do that, and there's no guarantee it will come off even after snapping the ribs!!