(I’ve moved this to project so you can get individualized responses based on your particular set up. 
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Sounds very practical. And sure, lots of people do that. There are all different kinds of devices that you can use. Basically the master device will send a message to the SmartThings hub which will then send the message to the other individual switches or groups of them as you like. See the following for possible devices for your fifth position. Some are battery powered and some are mains powered.
The other alternative would be to use a $20 Wi-Fi phone and set it up as a home automation dashboard. That way you could do additional options if you wanted.
SmartTiles is a very popular third party dashboard app that’s worth considering:
www.smarttiles.click