I did a bunch of research this evening on MacBook Pro displays and found that the issue I’m having might not be with the entire LCD itself (an image on which is faintly visible) but with the inverter board, which powers the backlights. In a $40 experiment, I ordered one on eBay from a reseller in England (there was nobody here in the states with the model number I need), and when it comes in I’ll finally crack the case and see if that’s the issue.