Nope.
It is basically OK but this is what I use:
Programs and then starts uploaded code to run completely automatically.
I very much doubt that, even if the Flash were rated for it. 
So get the module I linked.
Connect to them. They are general I/O pins. Just note that you must not have them pulled down, specifically on power up. You can connect a button to ground as long as you know it will not be pressed when you power up.
But do remember that the ESP-01(S) actually has four GPIO pins available in your target design. 