are you gonna keep a roo? that could become a problem as well, other then that it should be ok, we kept rabbits with chickens for years, but bedded with hay, (we cut are own and its a lot cheaper then straw) and that always kept the dust down
Duck poo is so messy, I don't think I would keep a rabbit with ducks the same way I do with my chickens. The rabbits would end up ingesting a LOT of duck poo as they clean themselves, more so than with chickens I believe.