Is it possible to apply for the Deutschlandstipendium outside the standard period of study?

No, the Deutschlandstipendium is aimed exclusively at students who are within the standard period of their study programme. These are not criteria set by JLU but a stipulation of the “Gesetz zur Schaffung eines nationalen Stipendiumprogramms (StipG)” (Law for the Creation of a National Scholarship Programme).