How to remove selected option from the option list in select2 multiselect and show selected options in the order they are selected

Part #1 of Q:

You can do a CSS trick to hide selected item like this:

.select2-results__option[aria-selected=true] {
    display: none;
}

Part #2 of Q:

Also you can do a JQuery trick to force selected items to end of tags box, ( by getting selected item on select, detach it (remove it), then reAppend it to tags box, then call “change function” to apply changes ):

$("select").on("select2:select", function (evt) {
    var element = evt.params.data.element;
    var $element = $(element);
    $element.detach();
    $(this).append($element);
    $(this).trigger("change");
});

Finally Updated JsFiddle, I hope it works for you, Thanks !

Edit #1

You can Clear All Selected by this call (apply Null values):

$("#dynamicAttributes").val(null).trigger("change"); 

on Button:

$('#btnReset').click(function() {
    $("#dynamicAttributes").val(null).trigger("change"); 
});

Updated Fiddle #2