I think 4chan came to the conclusion that the chart is actually Lelouch's doing...so all of the information on it is based on his knowledge. This covers why Nunnally and Sayoko were listed as dead when they proved to be and also explains why Cornelia wouldn't be listed as deceased. Lelouch doesn't know about her death yet. He also hasn't been told that Sayoko is still alive yet, so that's why she's still marked as dead.
Oh, Lelouch, only you would keep such a sketchy chart to keep track of the states of your friends, enemies, and what have you.
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Oh, Lelouch, only you would keep such a sketchy chart to keep track of the states of your friends, enemies, and what have you.