Hello Stig,
With regard to Baum, it is at least a possibility that another Flyable Fokker D.VII was interned in France I believe. Jon Guttman in Naval Aces of World War 1 Part 2 P.52 states the following "Flgmt Baum landed his damaged aeroplane in Holland and was interned"
So not so badly damaged that he was killed. Again nothing definite and it remains open until the serial number of his machine and its fate is known. Presumably whatever the state of the machine a record from the dutch authorities must exist?
BTW I'm searching the net at the moment and it looks like 115 was on the rudder when the aircraft landed according to this contemporary dutch source:
http://www.aerofile.info/wordpress/?page_id=1351
I believe this may be significant as the date 15 October is included , while Guttman P.49 says Engelfried and D.5584/18 were interned in Holland 15 September, although he must have been released fairly quickly if so as P.53 credits Engelfried as destroying a gasbag 26 October. Something seems not quite right here!
Regards,
Clint