It is. Just that it's the first such pair of aircraft that stay parked next to each other in all regimes, not just the one.
Apparently not! I learned from the video embedded in the article (just before the paragraph starting with "The Next Steps") that Scaled Composites has already built one: https://en.wikipedia.org/wiki/Scaled_Composites_White_Knight...
and from there I found a wikipedia category about them: https://en.wikipedia.org/wiki/Category:Twin-fuselage_aircraf... including another Burt Rutan design: https://en.wikipedia.org/wiki/Rutan_Boomerang
The Stratolaunch is just so much bigger.
It is. Just that it's the first such pair of aircraft that stay parked next to each other in all regimes, not just the one.