How close can separation be during a landing clearance?
According to the avherald article, the airport was operating below visual minima, thus no visual approach would have been possible. Unfortuntely, the ATC communication transcript is not available, so we will will not know whether the CAT III AutoLand approach by the B773 was communicated to ATC, which would not allow the Avro to enter the runway protected area during the B773's approach or whether this was a decision by the B773 crew only.

Since the airport was operating under CAT I procedures, the B773 is likely to have been cleared for a CAT I ILS approach. The Avro will have been cleared for departure before the B773 was cleared to land, ATC has most likely used a non-withheld landing clearance. 


  321.5 Landing clearance need not be withheld until prescribed separation exists if there is reasonable assurance that the appropriate separation will exist when the aircraft crosses the runway threshold. However, do not clear an aircraft to land before a preceding landing aircraft has crossed the runway threshold.


The runway is considered no longer occupied if the preceding departing aircraft has reached Vr and has rotated, although still being over the runway. If ATC can be reasonably sure that this will be the case when the landing aircraft crosses the threshold, the landing clearance can be issued.

The BFU bulletin reads:


  The B777 crossed the runway threshold of 08R at 12:09:09 in 40ft. Six seconds later, the BAe Avro crossed the opposite runway threshold at approx. 380ft.  


(Source: BFU Bulletin NOV 2011 - Translation: Own Work)

Is it typical for aircraft to be so close during approach and departure? Yes, aircraft can be close during these phases, depending on procedures in use and meteorological conditions. Aircraft can be asked to maintain visual separation to preceding traffic in VMC, however without the full transcript of the ATC communication, this will not be answerable in regards to your scenario in Munich.