Not sure about the Grieff VB ! Although it has the stripes, they were only painted on to allow passage back to the UK for evealuation, after capture. I had a feeling someone might pick this aircraft!!
I do tend to agree that the GB should be only allied aircraft, with AEAF stripes, at and following D-Day, as the title strongly suggests. As mentioned, we've had a GB specifically for Luftwaffe fighters, and other axis types are well covered in the MTO and Heavy Hitters GB's, both of which were wide open for choice. I do feel that allowing Luftwaffe aircraft as part of this GB is repeating at least part of the Defence of the Reich GB, at the possible expense of the main subject, D-Day stripes!
There are many more opportunities for us all to model our favourite subjects, be they well known or more obscure, and those future GB's already listed exhibit a wide variety of periods and types, with the opportunity to add more for the future.
However, if it is the overwhelming choice of the members to include Luftwaffe types, involved only in the campaign, then so be it. But, enemy aircraft would have to be involved directly in the immediate D-day period, otherwise the field could broaden to encompass virtually anything used by the axis powers after June 6th 1944, if enough excuses were provided!
Meanwhile, have a look at the list of allied aircraft I've posted separately in this section - there are many to choose from, some of which you might not have expected.