Can you paint damp treated lumber,laytex, and will it stick, I want to mix some sand in some outdoor paint then paint some steps I just built for traction.

No, don't paint damp wood with laytex paint, it won't stick. It doesn't matter what you mix it with, it won't stick for more then a couple of months, depending on what type of weather. You are only going to have to remove it all with a pressure washer once you need it painted to protect the wood.

Paint will not adhere very well to treated wood if exposed to very much direct sunlight.

Don't know why but it won't. If exposed to very much direct sunlight paint will chip and peel and require repainting about every two years. Horizontal surfaces peel more than vertical, probably because of direct sun razes and wood movement.

Harold is absolutely correct. In Florida, we have to let PT cure for 6 months before painting or staining successfully. Of course we have no option but to use PT wood. We have termites pretty bad in our area, so using dried wood is not really an option for outside.
Al