You will notice a major difference between a 266 (1MB cache on all of those) compared to a 233 with no cache. I have 233's with and without cache and you do notice a difference between them.
Hinges need replaced, if they are shattered then the video cable might get cut. Mostly thye just fail internally and the screen will not stand up.
You will need the heatsink or the chip will burn up. You can get HD cariers and heatsinks cheap on ebay or lemswap.