:: RR was pushed on Sessions and Trump by other DOJ Obama holdovers ::
We don’t know who was consulted for the RR recomm.
I recall looking this up months ago. There are a few names on the transition team (not Christie's) who had a handle on DOJ/US attorney area. IIRC, this part of the transition team was 100% not government people.
A Deep Dive Into The Department Of Justice Transition | Above the Law | David Lat | Jan 13, 2017
Rosenstein is a graduate of U. Penn. (Wharton)
So is Trump. Maybe some calls made ...
All the selections were deliberate. Rosenstein was not "pushed onto" Trump or Sessions.
In hindsight, imagine the ssorts of disasters if Christie's transition team finished the transition job.
Trump considering Maryland's Rosenstein for 'top position' in DOJ - Baltimore Sun - Jan 13, 2017
This article shows some "upside" to Rosenstein. Keep in mind that everything the news prints is fed to them, and they in turn massage it for narrative. But this piece paints Rosenstein as apolitical. That does not make him a friend of Trump by any stretch, just makes him apolitical. He could also be an apolitical sociopathic opportunist who prefers to fight his way to the top of the established order.
Rod Rosenstein: the little-known deputy AG making the official case against Comey - VOX - May 9, 2017
U.S. attorney in Baltimore is Trump's pick to be deputy attorney ... - WaPo - Jan 14, 2017