I would think that since the game begins at midnight CST, it would end at midnight CST as well. Celebs who croak on January 1 in the Eastern Hemisphere would still count as long as the clock hasn’t struck midnight in the CST.
As far as celebs ages, we normally go by the obits, but there are some famous people (especially in the middle-east) for whom reliable ages are iffy. Don’t know what will happen in such a case as that.
I do have one other thing. We might need a little rule addition for next year. I think we should prohibit the picking of people who were abducted in Iraq this year. This is tantamount to being on death row. Someone could conceivably fill their list with people like the Allawis and Margaret Hassan and then watch the points pile up as each one is murdered.