I have 2 Honda EU2000i's that I parallel and can run everything you have listed including the microwave. I have a surge protector that shows how many amps I am drawing and with air, TV, lights and fridge I pull about 20-25 Amps depending whether the converter is running. Paralleled EU2000s can provide roughly 27 Amps. At start up air will cause a surge so it is possible you are simply exceeding the capacity of them together. Your best bet is to get an ammeter and understand how much each appliance is drawing. I recently ran a full weekend in 95 degree weather with no issue.
