advice on controller

Yes to all 3. It comes with 2 floats for ATO. And they are plug and play, so you set them per the instructions, plug your pump into outlet #1, and you are good to go. I actually reprogrammed mine to only use one float. I set it to only run once per hour (so it does not constantly come on for a few seconds). My water level remains almost constant this way. I then use the other float for a high alarm. In my 55, I put it in my overflow in case it ever failed to re-start siphoning. It will turn off the return pump. In my AIO 28, I installed it in a small container that my skimmer overflow is plumbed into. In case it ever overflows, it will turn it off so it does not flood onto the floor.