Interesting about the air control valve, i once had a vehicle with similar problems starting in hot weather - turned out that the rubber lift gasket in the carburettor went soft in extreme heat and the answer was to manually lift the pot while turning the key, which was just doable, with long arms and a long screwdriver, but tended to draw incredulous looks from passers-by!
My other experience of intermittent ignition problems that were initially diagnosed as electrical, was eventually traced to changes in fuel formulation and a bio-alcohol blend which gummed up a nylon mesh pre-filter on the fuel pump. Again I wonder if the blend changes with the seasons where you are, giving rise to the seasonal nature of your problems?
All in all, though, the Honda sounds like the solution!