I'm not sure what your point is about Grant Morrison's villains being used.
It may be coincidence, I can subscribe to the idea that since the characters are only 4-5yrs old someone, some show runner might ask "Hey who are some new villains I can tinker with that don't have any preconceived ideas on them?" He/She goes through a list and hand picks these.
However, I can also believe that since Morrison is also held highly by the DC team that Johns/Didio might push some of Morrisons creations towards someone asking that hypothetical question. Afterall there are plenty of other "lesser known" Bat villains that could be used(I listed some I'd rather see than those chosen as dominant players), the two mentioned explicitly are Morrisons. Just strikes me as interesting, that's all I'm saying.