You can control lights , fans , humidifiers , portable , heaters , and outdoor electric appliances in accordance with the product specifications(Pay attention to the max current).
Yes. There is an option in HomeKit to either keep them as one unit or separate them. You can name and operate them independently.
Except for the U.S. product outdoor dimming plug MPD100/MPD100HK, other outdoor plug products do not support dimmer function.