Thank you, I'll see what I can found from the opposite side for these two claims.
Info for Flugzeugüberführungsgeschwader 1:
http://www.ww2.dk/air/misc/flug1.htm
And it should be a misprint and 3./JGr.ZBK should have been Stab/JG zbV (Jagdgeschwader zur besonderen Verwendung), a Stab formed to control a number of Gruppen:
https://www.ww2.dk/air/jagd/jgzbv.html