Last I saw, there was a list of 34 iirc.. names including a couple anonymous.. One source says 30. The next information release will be sometime(?) in June. Until then, there will be no announcements. The WSOP director says 40 for some reason.. probably including top pros that show a lot of interest in playing.
Since it's a million bucks, i doubt anyone already paid it. Instead, left it in their own bank accounts to earn interest.
The $50K deposit those 34 probably submitted is refundable, so that's not exactly "confirmed" imo. If something odd happens where nobody wants to show up, nobody is obligated to at this point.
My opinion is nobody wants to be stuck in a tiny field, and will wait to see what everyone else does before committing to it.