Can you mix latex polyurethane with latex paint?
If you want to keep your paint color pure and cover your object and/or project with 1 or 2 coats, I wouldn’t, it sounds like your trying to eliminate a step, I know they do it with stain and polyurethane but not with paint and poly. I think as long as its water-base poly & water-base paint (latex) its possible, try 1oz of paint, 1oz of poly and mix well and try it on a test piece to see if its to your liking. Good-Luck!