(1) Yes, that is true. I agree, it would have improved accuracy. Indeed, old celebs who didn’t die in 2015 (eg Castro) were likely to die in 2016. It would have needed extra biograph-parsing code though.

(2) Yes, this is true, and would have been the ideal strategy. Unfortunately, a lot of old bios have been expanded and edited a lot over the years, so this would have introduced a different, and horribly non-linear, bias.