I don't know if I'm qualified to respond on here, but there's a great article from Mark Kramer called the Demise of the Soviet Bloc and it goes into the domestic and international reforms that Khrushchev implimented in the years leading up to the collapse of the Soviet system.

I don't know if this answers your question as to the relative power of the Soviet hardliners, but I do know that Khrushchev did replace a number of Soviet officials during his first few years in office. This replacement afforded him greater flexibility in the years that followed because it allowed him to stick to his ideal of non-violent intervention.

While this certainly could have happened without the replacement of former upper-level officials, the fact that these newer leaders were appointed by Khrushchev generally meant that they were more loyal to him and therefore didn't challenge him when he decided not to send in the military to deal with political uprisings in the satellite states.

Hopefully someone else can answer your question more thoroughly but I hope that this is a good start.