create a pause before opening modal window to load scripts

If I am correct, it is because all the requests are made asynchronously by default, if you want the ajax request to be synchronized you must change the default value true to false in:

 $.ajax({
        url: '../reportes/cufinn',
        type: 'POST',
        async: true,
        dataType: 'json',
          data:{
            datos:'where estatus=0'
        },
    })

Here you can read a little more: link

The problem is that the two scripts run in the onLoad event, as you did there would be no way of knowing which of the two ran first. I do not think that if you put false the async works. I leave you another solution where I embedded the AJAX, in parameter success (I did not use the DONE method) When the first part ends, we immediately run the second part, thus chaining the process.

//Función similar a onLoad
$(function() {

  //Primera llamada de AJAX
  $.ajax({
    url: '../reportes/cufinn',
    type: 'POST',
    dataType: 'json',
    data: {
      datos: 'where estatus=0'
    },
    success: function(data) {
      //Callback del proceso 1
      for (i = 0; i <= data.length; i++) {
        if ((i % 2) === 0) {
          var c = ' bgcolor= "#E0ECF8"';
        } else {
          var c = '';
        }
        $("#datos1").append('<tr>' +
          '<td>' + data[i]['ejercicio'] + '</td>' +
          '<td>' + data[i]['periodo'] + '</td>' +
          '<td>' + data[i]['Movimientoef'].toUpperCase() + '</td>' +
          '<td>' + data[i]['Perdidaf'] + '</td>' +
          '<td>' + data[i]['Perdidaa'] + '</td>' +
          '<td>' + data[i]['Resultadof'] + '</td>' +
          '<td>' + data[i]['PTUPP'] + '</td>' +
          '<td>' + data[i]['PTUCC'] + '</td>' +
          '<td>' + data[i]['ISRR'] + '</td>' +
          '<td>' + data[i]['Nod'] + '</td>' +
          '<td>' + data[i]['UFINN'] + '</td>' +
          '<td>' + data[i]['difec'] + '</td>' +
          '<td>' + data[i]['SaldosA'] + '</td>' +
          '<td>' + data[i]['INPCMM'] + '</td>' +
          '<td>' + data[i]['INPCFAA'] + '</td>' +
          '<td>' + data[i]['Fact'] + '</td>' +
          '<td>' + data[i]['SaldoAAc'] + '</td>' +
          '<td>' + data[i]['Divp'] + '</td>' +
          '<td>' + data[i]['SaldoTT'] + '</td>' +
          '</tr>');
      }

      //Segunda llamada AJAX dentro del callback del proceso 1
      $.ajax({
        url: '../reportes/cufinn',
        type: 'POST',
        dataType: 'json',
        data2: {
          datos: 'where estatus=1'
        },
        success: function(data2) {
          //Callback del proceso 2
          for (i = 0; i <= data2.length; i++) {
            if ((i % 2) === 0) {
              var c = ' bgcolor= "#E0ECF8"';
            } else {
              var c = '';
            }
            $("#datos2").append('<tr>' +
              '<td>' + data2[i]['ejercicio'] + '</td>' +
              '<td>' + data2[i]['periodo'] + '</td>' +
              '<td>' + data2[i]['Movimientoef'].toUpperCase() + '</td>' +
              '<td>' + data2[i]['Perdidaf'] + '</td>' +
              '<td>' + data2[i]['Perdidaa'] + '</td>' +
              '<td>' + data2[i]['Resultadof'] + '</td>' +
              '<td>' + data2[i]['PTUPP'] + '</td>' +
              '<td>' + data2[i]['PTUCC'] + '</td>' +
              '<td>' + data2[i]['ISRR'] + '</td>' +
              '<td>' + data2[i]['Nod'] + '</td>' +
              '<td>' + data2[i]['UFINN'] + '</td>' +
              '<td>' + data2[i]['difec'] + '</td>' +
              '<td>' + data2[i]['SaldosA'] + '</td>' +
              '<td>' + data2[i]['INPCMM'] + '</td>' +
              '<td>' + data2[i]['INPCFAA'] + '</td>' +
              '<td>' + data2[i]['Fact'] + '</td>' +
              '<td>' + data2[i]['SaldoAAc'] + '</td>' +
              '<td>' + data2[i]['Divp'] + '</td>' +
              '<td>' + data2[i]['SaldoTT'] + '</td>' +
              '</tr>');
          }
        }
      });
    }
  });
});

If I understand you correctly, I think you could solve it using callbacks . That is, send "output2 ()" by parameter to "output ()" so that it executes when the latter ends.

For example, I have the function "output ()" that receives a function by parameter. The "output ()" function makes an asynchronous call and when it is finished, execute callback () .

function salida(callback) {
    $.ajax({
        url: 'someurl',
        type: 'POST',
        dataType: 'json',
        data: {
            // json data
        },
        success: function(data) {
            // do something

            if (typeof(callback) === 'function')
                callback();
        }
    });
}

Now, the way to call this function would be:

salida(function(){
    // do something after execute
});

or also:

function salida2() {
    // do something
}

salida(salida2);