Google Sheets Script to send and email alert and color a row when a task is late. It assumes the sheet has the following columnsLabels: Features, Status,DateDue.

EdittingChanges.gs

function onEdit(e) {
  var activeSheet = e.source.getActiveSheet();
  if (activeSheet.getName() !== 'lookup') {
    var range = activeSheet.getDataRange();
    editTasksSheet(range, e);   
  }
  
}

function editTasksSheet(range, e){
  var data = range.getValues();
  var columnEditted = e.range.getColumn()-1;
  var rowEditted = e.range.getRow()-1;
  var valueInput = data[rowEditted][columnEditted];
  var dateDueCol = getColumnByName('DateDue', data);
  var statusCol = getColumnByName('Status', data);
  if (dateDueCol < 0 || statusCol < 0){
    return;
  } else if (columnEditted === dateDueCol) {
    var rowRange = range.offset(rowEditted, 0, 1);
    // var dateInput = data[rowEditted][columnEditted];
    formatBasedOnDate(rowRange, valueInput);
  } else if (columnEditted === statusCol) {
    if (valueInput === 'done') {
      var rowRange = range.offset(rowEditted, 0, 1);
      rowRange.setBackground('#c8e6c9');
    } else {
      formatBasedOnDate(rowRange, data[rowEditted][dateDueCol]);
    }
  }
}

function formatBasedOnDate(rowRange, dateInput){
  Logger.log("in format Based On Date functon");
  if (!isValidDate(dateInput) && dateInput !== '') {
    var ui = SpreadsheetApp.getUi()
    ui.alert('The date input is not valid');
  }
  var currentDate = new Date();
  var newDate = new Date(dateInput);
  if (currentDate <= newDate || dateInput === '') {
    rowRange.setBackground('#FFFFFF');
  } else {
    rowRange.setBackground('#ffcdd2');
  }
}


function getColumnByName(colName, data) {
  var col = data[0].indexOf(colName);
  return col;
}

// From http://stackoverflow.com/questions/1353684
function isValidDate(dateInput) {
  if (Object.prototype.toString.call(dateInput) !== "[object Date]")
    return false;
  return !isNaN(dateInput.getTime());
}

LateAlert.gs

// This script checks the date of due tasks
// It then compares them to the current date
// If the script is late, it sends an email to the people in the emails list
// Warning them of the status
// Thus the people can either change the due dates or mark the tasks complete
function setupGlobalVariables() {
  var scriptProperties = PropertiesService.getScriptProperties();
  scriptProperties.setProperties({
    'LOOKUP_SHEET' : 'lookup',
    'DATEDUE_COLUMN' : 'DateDue',
    'FEATURES_COLUMN' : 'Features',
    'STATUS_COLUMN' : 'Status',
    'EMAILS_COLUMN' : 'Email'
  })
}

function mainFunction() {
  setupGlobalVariables();
  var scriptProperties = PropertiesService.getScriptProperties();
  var ss = SpreadsheetApp.getActive();
  var allSheets = ss.getSheets();
  var emails;
  var notificationMessages = [];
  
  for (var s in allSheets){
    var sheet = allSheets[s];
    var range = sheet.getDataRange();
    var data = range.getValues();
    var sheetName = sheet.getName();
    Logger.log(sheetName);
    if (sheetName === 'lookup'){
      emails = getEmailsToNotify(data);
      continue;
    } else {
      notificationMessages[sheetName] = getNotificationsFromSheet(range);
    }
  }
  sendEmail(emails, formMessage(notificationMessages), ss.getName() + "Alerts");
}

function formMessage(notificationMessages){
  var message = "";
  for (var key in notificationMessages){
    if(notificationMessages.hasOwnProperty(key) && notificationMessages[key].length > 0){
      message += makeTitle("** Late tasks from sheet: " + key);
      for (var i=0; i<notificationMessages[key].length; i++){
        message += "- " + notificationMessages[key][i] + "\r\n";
      }
      message += "\r\n\r\n";
    }
  }
  return message;
}

function makeTitle(title) {
  // title += "<br/>";
  var underline = "";
  for (var i=0; i<title.length; i++){
    if (title[i] == ' ') continue;
    underline += "=";
  }
  var message = title + "\r\n" + underline + "\r\n";
  return message;
}

function getNotificationsFromSheet(range) {
  var data = range.getValues();
  var dateDueCol = getColumnByName('DateDue', data);
  var featuresCol = getColumnByName('Features', data);
  var statusCol = getColumnByName('Status', data);
  if (dateDueCol < 0 || featuresCol < 0 || statusCol < 0 ){
    return ["error : Sheet does not follow expected format"];
  } else {
    messages = getLateDateDues(dateDueCol, statusCol, featuresCol, range);
    return messages;
  }
  // checkLateDateDues(dateDueCol, statusCol, featuresCol, data);
  // return ['this is cool', 'this is another one', 'I love this'];
}

function getEmailsToNotify(data) {
  var emailCol = getColumnByName(PropertiesService.getScriptProperties().getProperty('EMAILS_COLUMN'), data);
  var emails = [];
  if (emailCol < 0)
    return emails;
  for (var i=1; i<data.length; i++) {
    var email = data[i][emailCol];
    if (email.trim() !== ''){
      emails.push(email);
    }
  }
  return emails;                 
}

function sendEmail(emails, message, subject){
  for (var i=0; i<emails.length; i++){
    MailApp.sendEmail(emails[i], subject, message);
  }
}
function getLateDateDues(dateDueCol, statusCol, featuresCol, range) {
  // loop through the date due column only
  var data = range.getValues();
  var dateNow = new Date();
  var messages = [];
  for (var i =0; i<data.length; i++) {
    var dateDue = new Date(data[i][dateDueCol]);
    var rowRange = range.offset(i, 0, 1);
    if (dateNow > dateDue && data[i][statusCol] !== 'done'){
      messages.push(data[i][featuresCol] + ' was due on ' + dateDue);
      rowRange.setBackground('#ffcdd2');
    }
  }
  return messages;
}

function getColumnByName(colName, data) {
  var col = data[0].indexOf(colName);
  return col;
}

function createTimeDrivenTriggers() {
  ScriptApp.newTrigger('mainFunction')
      .timeBased()
      .everyDays(1)
      .create();
}