Only way to add new row to jqgrid using inline editing is to use use jqGrid 4.3 inline navigator add button. However in this case formatter actions save and cancel buttons are not available.
Also as desxcribed in Oleg comment in How to add toggle button from jqgrid toolbar to autogenerated context menu if other row has selected and inline edit is terminated, row still remain in edit mode.
How to synchronize formatter actons and online navigator buttons: pressing add, edit in toolbar or edit formatter action button or double clicking in row starts online edit. Save and cancel buttons in both places terminate online edit.
