Copy notes between Google Sheets

clearChildNotes.gs

// If you make a mistake, this will clear all notes from the child sheets
function clearChildNotes() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet2');
  var buildings = sheet.getRange(1, 1, sheet.getLastRow(), 3).getValues();
  
  for(var i=0; i<buildings.length; i++) {
    SpreadsheetApp.openByUrl(buildings[i][1]).getSheetByName('Sheet1').clearNotes();
  }
}

syncNotes.gs

function syncNotes() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet1');
  var data = sheet.getRange(2,1,sheet.getLastRow(), sheet.getLastColumn()).getValues();
  
  for (var i=0; i<data.length; i++) {
    
    if(data[i][0]) {
      var url = getSheetUrl(data[i][0])
      
      if(url) {
        
        // This returns an array of notes as an object so you can write a row at a time rather than a cell at a time.
        var notes = sheet.getRange(i+2, 1, 1, sheet.getLastColumn()).getNotes();
        
        // Set the value on the child sheet
         var child = SpreadsheetApp.openByUrl(url[0]);
         child.getSheetByName('Sheet1').getRange((i+2 - url[1]), 1, 1, notes[0].length).setNotes(notes);
      }
    }
  }
}

// Helper function to get the sheet URL for the child sheet
function getSheetUrl(building) {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet2');
  var buildings = sheet.getRange(1, 1, sheet.getLastRow(), 3).getValues();
  var url;
  
  buildings.forEach(function(el) {
    if(el[0].toString() == building) {
      url = [el[1], el[2]]
    }
  })
  return url;
}

updateOffset.gs

function updateOffset() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  // Get the offset helper and data as a 2D array
  var offsetsSheet = ss.getSheetByName('Sheet2');
  var offsets = offsetsSheet.getDataRange().getValues();
  
  // Get the staff list as a 2D array
  var torSheet = ss.getSheetByName('Sheet1');
  var torList = torSheet.getDataRange().getValues();
  
  // Loop each building
  for(var i=0; i<offsets.length; i++) {
    for(var j=0; j<torList.length; j++) {
      if(offsets[i][0] == torList[j][0]) {
        offsetsSheet.getRange(i+1, 3).setValue((j-1));
        
        // Stop this loop and index i+1
        break;
      }
    }
  }
}