I've always felt Ghoul Rush was the most underwhelming feeling combo, and that's the only one that isn't being changed? It only works as intended if it's killing enemies instantly. If it doesn't, then you're just awkwardly walking into them the whole time you're doing it.
I know for a fact that being affected by Ensnare from a Radiation Sister will break your ability to do executions. On Hounds, this merely causes you to default to the failsafe stab animation, however the failsafe is disabled during certain segments with Sisters, so instead you'll just lose the prompt and can't do anything until either she gets back up or (If you're doing the final stab in the showdown) you restart the mission.