That split around the inside bezel is an easy fix IMO. You can use some good, translucent plastic glue (test the glue on a really hidden part first).

I've had a couple of iMac G3's with cracks like that and so long as the bezel isn't cracked all over, you can glue it and because the plastic outer bezel is frosted you don't even see the repair *unless you look really really close because you KNOW where it is*

You might get the iMac apart and the bezel just keeps spitting and all the screw mounts just snap off etc. I've had one or two that bad!