Rubio is a perfect ringer for them: an internationalist who is able to babble some conservative-sounding rhetoric when he has to. Kind of like a more suave and slick version of George W. Bush. Maybe Jeb can pick Rubio as his running mate if they won't let him get away with picking George "Viva La Raza" Prescott.
You have it exactly.
The original neoconservatives came out of the cold warrior wing of the Democratic party. Liberal internationalism is what it was called. They joined the Republicans during the Reagan years for its muscular foreign policy. But they also brought along their liberal domestic ideas and have been working to mainstream them in the GOP ever since.
I doubt that they will ever succeed in convincing conservatives but they have had a lot of success with the Republican establishment. Dubya, Romney, Jeb Bush, Rubio, the whole open borders/ amnesty crowd.