Hi Johan
Grufl 12 was establish #officially" in Mar 1917, this stab unit eventually had its origin from old Grufl D of 1 Army...
As many other Grufls they were "moved" around because of the activities on different front areas...
I dont knew exactly when they arrived to Flanders in 1918 because I miss some weekly Kofl 4 reports...
They were later re-named to
Grufl Nord and lastly to
Grufl Marine Korps...I dont have the re-organization plan in Jun 1918 as I am also missing this weekly Kofl 4 report...
However many air units had left Flanders already in late May 1918 and many of the "rest" left Jun 1918....
The unit which was created from MFFA I and II was the
Masosta....they had nothing to do with protection of minesweepers or the coast...
hope it helps a little
Gunnar