Airflow helps the fog situation, I often ended up cycling with my head tilted down looking over the top of the glasses. Not pleasant. Saliva (eeew...) works as well as soap. You can get antifog solutions for windscreens, but I never tried this 'coz I don't want that stuff near my eyes.
I found that in serious rain either the lenses would fog up or there would be so many raindrops I couldn't see enough to ride safely.
After investigating prescription sunnies I decided to boot it all and go back to contact lenses. This has worked really well for me. If my sunnies or clear safety glasses (for wind) fog up or get too we I can just take them off. The sunnies are much lighter and less expensive than my -8.00 prescription lenses!