Heat being left on set to low?
There is no need to "drain the toilet, tank and bowl, or the traps.
There's also traps and water trapped in the shower and or tub, where the washing machine drains, and inside the washing machine.
Just add the antifreeze to them.
If you do drain the water heater, when you start it back up remove the aerator from the closest fauset and turn on the hot water side wide open when filling to make sure the tank is full of water before turning back on.
If the heats going to shut off the main water line needs to be shut off and lines blown out with air one at a time, making sure you also disconnect the lines to the washer and the toilet to blow out all the water.
Lines need to be blown out before the water heater tank gets drained.