The AT29C256 is more than 15 years old and may no longer be manufactured. Unlses you find a ditributor with stock you're likely to be SOL. All American is the only ditributor listed on the Atmel website, but the quantity listed is -200, and they were -90JI in any case. I'm not sure what this means, but I don't think it is good news.
The other part has no useful markings. It is very likely a custom part with no publicly available datasheet or information. Again I think you are SOL.