I think she is pussy whipping Little Finger, and its the only of two in westeros that could have possably controlled what seems to be the most cunning and underhanded man in westeros.
As for the hounds infected bite- well drogo dies of one, although it was helped along by the mad witch lady bitch...
I think maybe Tywin and the others think the mountain didn't die... also I was surprised at the quickness that tywin stood up and was like "f- you tyrion your toast" all this time you knew he didn't /like/ tyrion or would not overly mind if he bit it- but not so much that he would essentially kill him- almost himself. I think that will change of Tyrion interacts with his father and his sister- his father knows he didn't do it, his sister well she is all sorts of crazy so whatever... when tyrion survives, and I am sure he will just by my hopes and dreams lol- he will give the finger to his pops and do...something I dunno... or just leave and go pee off the wall again.
I also think the audience hates that Joff got off easy in his death compared to obryn-- although really that first punch to the head so hard almost all his teeth where shot out would have knocked him out cold, the shock of getting your eyes gouged out may have brought you back but the sheer trauma and resulting shock would have passed you out almost instantly again that you would not really be aware of your head getting smashed in...
As for the question of if the mountain admitting he killed them at the end would matter... nah- no one gives two shits.. Ned Stark had a signed sealed decree from the king and no one flinched when it was torn up or gave two shits about that.