According to ketile, snippet code below does work on Chrome OS but not on Android.
He can't get multiple notifications to work. Is that a known issue on Chrome Dev for Android?

  ...
  .then(() => bleService.getCharacteristic(pressureCharacteristicUUID))
  .then( characteristic => {
    log('Got pressureCharacteristic');
    pressureChar = characteristic;
    return pressureChar.startNotifications();
  })
  .then(() => {
    pressureChar.addEventListener('characteristicvaluechanged',handleNotifyPressure);
  })
  .then(() => bleService.getCharacteristic(humidityCharacteristicUUID))
  .then( characteristic => {
    log('Got humidityCharacteristic');
    humidityChar = characteristic;
    return humidityChar.startNotifications();
  })
  .then(() => {
    humidityChar.addEventListener('characteristicvaluechanged',handleNotifyHumidity);
  })
  .then(() => bleService.getCharacteristic(temperatureCharacteristicUUID))
  .then( characteristic => {
    log('Got temperatureCharacteristic');
    temperatureChar = characteristic;
    return temperatureChar.startNotifications();
  })
  .then(() => {
    myCharacteristic.addEventListener('characteristicvaluechanged',handleNotifyTemperature);
  })
  **/

Full code is available at https://github.com/ketile/ketile.github.io/blob/e3d018f37ddfb8f511c0baf89cf1fcb37476e8e5/experiments/responsive-ui/javascript/weather_station.js#L263