It really is hit and miss, I had a middle home button screw that would not budge, managed to bend the metal clip and get the whole thing out , put it in the new phone and luckily it still worked . Ive done lots of these and have had about 4 or 5 screws that wouldn’t budge . As soon as you fail a couple of times, it’s stripped
you can use a 4 button on a 4s screen, just trim the flex off and leave the metal bit attached. It actually makes the 4s button better, it is more clicky because it has two clicky bits pushing against each other.