Re infighting: In New Hampshire IOTL Bobby came within 3100 votes of receiving more write-in votes for Vice President than LBJ for President. That's without a publicly endorsed effort. Reverse that margin and LBJ will go off the deep end. If Rocky is nominated, the violent Southern objections become irrelevant.
Re deep freze: Oh, Bobby anticipated that IOTL: "if I speak out, he'll put me in a deep freeze. He doesn't have to speak to me (like Nixon/Agnew) and it would not be a good relationship. On the other hand, internal, clandestine opposition... That's a pretty disloyal operation."
I have no doubt that Bobby would not want to derail his plans to raise his hand and take the Presidential oath on January 20, 1973. It would be at best the political relationship between Reagan and Bush I and as for the personal relationship, well let's leave that to the ample available audio.
RFK was very personally friendly with the press: Hickory Hill was crawling with journalists and even
some native (not JFK-inherited) LBJ aides on any given weekend. He was very cautious not to even trash-talk in his Senate office with his aides. But just looking in his eyes in any picture of the two tells the whole story.