Wasn't Hong Kong Fooey's real identity a police station janitor? He should be very familiar with the hygiene and usage of toilets. It only lasted one season, and I agree that the theme intro was its redeeming feature. Otherwise, I seem to recall that it's the same joke repeated again and again.
You can't really have Marvin without Duck Dodgers IMHO. I've never seen the DD series from the early 2000's. I think it won some awards so I might check it out when it becomes available on DVD.