FBI is an executive branch agency so whoever you elect President has total control over it.

Jefferson is an Angry Democrat.

well, it obviously depends on the circumstances of Rosenstein's departure. if Congress impeached Rosenstein according to the paths laid out by the law, the DoJ imho would have a hard time being petulant and obstructive.
what you suggest imho would only apply if Trump was clearly the driving force behind Rosenstein's ouster.

Uh, duh. Congress impeaching Rosenstein has little to no chance of happening - i don't see it, especially when Paul ryan has said he respects the special counsel investigation.

Only way I could see it happening (via Congress) is if mueller's investigation drags on to 2019 with no end in sight.

... which I totally expect to happen. Imho, Mueller's probe serves, among other things, as an instrument for the military-industrial complex to keep Trump's russophilia/putinophilia in check.

150 or so days is a long time. Idk.

if? seriously? as if that wasn't crystal clear to any sane human being...

To be fair, House G.O.P freedom caucus (basically tea party 2.0) is about as insane/stupid as trump.

idk if i'm misunderstanding this. you are suggesting trump is the one that wants rosenstein out?
if this is so, you should hear about a man named jim jordan

from what i read it was 7 rhinos from the house....it's going to take a shitload more support to make the happen lmao...aka not going to happen