[Django]-How to dynamically make an existing non-abstract django model, abstract?

Why not, in app1

AbstractBaseModelA(models.Model):
    # other stuff here
    class Meta:
        is_abstract=True


ModelA(AbstractBaseModelA):
    # stuff

in app2:

MobelB(AbstractBaseModelA):
    # stuff

Sorry if I’ve misunderstood your aims, but I think the above should achieve the same end result.