With the Shazam movie with The Rock NOW scheduled for a 2019 release...
How about a Mary Marvel live-action-series in the interim? I had read that the DC movie & DC TV universes would be completely separate from each other. Remember when Smallville was still on TV when Superman Returns came out in 2006? And now with the Batman prequel GOTHAM currently airing on FOX TV and with Batman scheduled to appear in Batman v. Superman sometime next year or the year after there would be no conflict. The same can be said with The Flash TV series on the CW and now with the announcement of a separate Flash live-action movie coming out in a couple of years with a differnt actor playing the titular role given that the TV show would still be running in conjunction when the movie comes out.
In regards to Mary Marvel they could use the combo of her Golden Age & Power of Shazam origin. Mary Batson adopted by Nora Bromfield is part of the Golden Age origin part. In regards to the POS origin, instead of Mary remaining a teenager in Marvel form like Freddy Freeman (Captain Marvel Jr.) from the golden age, Mary Marvel could be an adult doppelganger for her late mother, Marilyn Batson in the same way Captain Marvel is a doppelganger for Billy & Mary's father, C.C. Batson.
Mary Marvel's origin could be as follows: As some comic book heroes's origins are being re-invented for TV, Mary Batson could get her powers first instead of her brother Billy in the same way that he did: That the wizard Shazam could chose her to be his first Marvel to protect Fawcett City.
It wouldn't make sense that if Mary Batson and Mary Marvel were played by the same actress wouldn't the TV audience question how nobody sees the resemblance between MB & MM? Kind of like why nobody saw the resemblence between Clark Kent & Superman give that he wore only a measly pair of glasses. Having Mary Marvel be played by a totally different actress makes some sense.
For Mary Marvel, Amanda Righetti (The Mentalist), at 5'8", would be great.
For Mary Batson this girl would also be perfect:
http://www.imdb.com/name/nm3187320