Does anyone know if it's possible to use the balance wheel from a Caliber 3285 in a 3235 movement, or is there absolutely no chance due to physical differences between them?
3285 is a base 3235 movement so the two gen parts are the same.
If you want to try this, your best chances for success will come from using the same factory parts, DD with DD/VS, SH with SH/VR. Those two factories' hairsprings are coiled in opposite directions so they are not interchangeable. Pay attention to that.
Another option to fix an ailing 3235 movement is to replace the balance wheel assembly, assuming the bridge is OK. This is not that difficult, though certainly not a beginner level task.
You just have to brush on some acetone (Goof off) to the adhesive anchoring the hairspring to the stud (point A), then slide the hairspring out of the regulator arm slot (point B). Insert the new hairspring in and anchor the end to the stud with a drop of epoxy.
3235 balance assembly is not expensive