If I remember correctly, those parts labeled F258 (the one that came off) are standard CMOS logic chips or buffers -- buffers I think. And so it should be possible to source brand new ones from Digikey.

The ROM SIMM is replaceable, even if it's been kilt. And socket is harder to find, but also replaceable. One of our members had a source for the 64 pin sockets, as I recall. Can't remember who it was.

The big issue, I think, is whether or how many traces and vias were eaten and whether the corrosion reached the CPU pins and what that little chip in the middle of the big white stain is.