I got Grimm, basically yelled it at the tv ;). Of course I've seen it and stopped watching some in season 4 (?) but saw enough to know the show.
I was thinking JFK because he was killed in office, therefore less time to meet the queen. But now I think about it, of course she met Kennedy. So Johnson make's sense as it's still the same time period her kids were born in. I also heard 3rd child.