What is the allowable shear (lbs in bearing) for 3" Builder's Choice #25 star drive screw?

There are too many factors that play into this. First thing first, Screws or nails should not be used for anything other than to hold boards together. Boards should be set on top of other boards then screwed down to make sure it stays in place. This way all the weight of the board is transferred to the other board and not the screw. If you do plan on having the screw hold actual weight it would be a temporary thing. Old barns stay together for 100+ years by being built like a Lincoln log set where every board sets directly on top of another board. Nails or screws only hold the set together. Treated screws only have a coating on them that prevents the chemicals in the treated lumber from causing the screws to deteriorate. So in short, You can use a screw like this to attach something very heavy to a ceiling, but would be unsafe because the head of the screw is not designed to hold weight like that. Instead you should use Lag Bolts and washers for long term strength.

I would think at least equal to a 3" ardox nail if not more