>Is it O.K. to use a non-fat soybean flower in making a pollen substitute?
 
 
Yes. That is what pollen substitute is actually. And from my experience
(FWIW), bees will take any grain dust in the spring to rear brood with. One
farmer I rent to can't hardly add corn to his cattle feeders until late at
night right now. The feeder and the ground around them are covered with
foraging bees. He thought it was weird how they shined up his corn in a days
time.