Answer:
It's highly unlikely. They were involved in the movie business at different times.
With the exception of a couple of episodes of The American Sportsman, on which Howard Hall worked as cinematographer, his first industry experience was with "An Incidental Kill" in 1987.
Howard Hughes started as producer of "Swell Hogan" in 1926, and ended his movie career with the extraordinary "Jet Pilot" in 1957. Hughes lived as a recluse from 1966 on.
"I'm not a paranoid deranged millionaire. Goddamit, I'm a billionaire." - Howard Hughes.