Here's one way:
Put all the parts that go before void setup together.
Put all the parts in void setup together.
Write a blink without delay section to run the rest quasi- concurrently:
add these to your declarations:
unsigned long previousMillis();
byte sketchSelect = 0;
void loop(){
if (millis() >=previousMillis){
previousMillis = previousMillis+100; // each gets 100mS, then next one start
sketchSelect = sketchSelect +1;
if (sketchSelect == 4){ sketchSelect = 1;}
}
switch (sketchSelect){
case 1:
// sketch 1
break;
case 2:
// sketch 2
break;
case 3:
// sketch 3
break;
} // end switch
} // end loop