With Garlicdesigns superlative never build designs to hand. I could answer my own question as to what the Germans may have had if they had put a dual purpose gun into production.
Very easy, the scout cruiser class with 8x127mm dual purpose guns in four twin turrets. The other AA weaponry have also been upgraded with 4 by twin 50mm and 4 x 37mm twins (based on the captured 40mm twins from the Dutch in 1940). The pair of quintuple torpedo tubes remain. The high speed and long range required for escorting the battleships remains.
I have a lot of German drawings floating around, I may have to have a look at a German equivalent to the Fisherless RN AU.