[WEMOS D1 mini] Start Board with pin Activated.... crash?

Using Arduino Programming Questions
1

Hello Everyone,
I would like to use a wemos D1 mini (ESP12) for a project (replace an old sanguino)

The configuration is a Wemos D1 mini, a simple pushbutton (with resistor to ground) on pin D3, and SDA et SCL ports to 3 MCP23017 with pullup resistors.

I have two problems, quite similar i think:

1- In my program, when the board is powered, if D3 input is activate, the board has to activate update function by ota. The problem: if the pushbutton is activate before the board is powered, the program don't start

Here is the test program i did

byte mode_update = 0;
int ledState = LOW;
unsigned long previousMillis_manuel = 0;
unsigned long previousMillis_OTA = 0;
const long interval_manuel = 800;
const long interval_OTA = 50;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(D3, INPUT);
  Serial.begin(115200);
  delay(3000);

}

void loop() {

  if (mode_update == 0 && !digitalRead(D3) || mode_update == 1) {
    mode_update = 1;
    Mode_update();
  }
  else {
    mode_update = 2;
    Mode_manuel();
  }
  digitalWrite(LED_BUILTIN, ledState);
}


void Mode_update() {
  Serial.println("Programme Update OTA");
  unsigned long currentMillis_OTA = millis();

  if (currentMillis_OTA - previousMillis_OTA >= interval_OTA) {
    previousMillis_OTA = currentMillis_OTA;
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }
  }
}


void Mode_manuel() {
  Serial.println("boucle manuel");
  unsigned long currentMillis_manuel = millis();

  if (currentMillis_manuel - previousMillis_manuel >= interval_manuel) {
    previousMillis_manuel = currentMillis_manuel;
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }
  }
}

2- I have nearly the same problem, my D1 mini use 3 MCP23017 on the I2C ports. But some time the program don't start because of I2C ports plug in?

Does someone know how to fix that?
thanks for your help