Oh well… after spending literally days with annoying tries to unstretch some areas of this Drorc (yeah, that’s right, by now this weird dragonish orc is called the Drorc) I stumbled upon my very stupid mistake:
I did NOT apply the shrinkwrap
So I just tried it and you see the result on the screenshot. I had several greenish areas before which are entirely gone just by applying the shrinkwrap modifier.
The light blue parts you see in the left are all on the belly of the Drorc and some are so weird that it must be a mistake from blender to show it light blue, but I do not care that much because the belly isn’t the part most seen of the Drorc (if so it must have been defeated and I do not hope so )
So, if you have an issue with not being able to deal with the stretching in a reasonable way check if you have applied the shrinkwrap. It might help you too.