Looks like the modern toolkit’s Cell Editing Plugin does not support events as it is designed in the classic toolkit. I have added the missing feature in form of override.

The override does not add all the events to the grid, it just shows to you how you can implement the missing features in the modern toolkit (version 6.5.3).

Ext.define('overrides.grid.plugin.CellEditing', {
    override: 'Ext.grid.plugin.CellEditing',

    getEditor: function (location) {
        var editor = this.callParent([location]);
        if (editor) {
            this.addEditorEvents(editor, location);
        }
        return editor;
    },

    addEditorEvents: function (editor, location) {
        editor.on('beforestartedit', function () {
            var handlerResult = this.getGrid().fireEvent('beforeedit', location);
            if(handlerResult === false) {
                editor.hide();
            }
            return handlerResult;
        }, this, {
            single: true
        });

        editor.on('complete', function () {
            this.getGrid().fireEvent('edit', location);
        }, this, {
            single: true
        });
    }
});

In the sample grid you can edit only rows with even indexes.  As you can see from the code I am sending location object to the ‘beforeedit’ and ‘edit’ events for farther handling.