Of course Baine & Vol'jin would disagree with the attack on Theramore. Baine is a pacifist and new to his rank as Leader and Vol'Jin knew Theramore was once neutral with Orgrimmar under Thralls leadership.

There is no way either one of them would've agreed with the plan to deal with the legitimate threat of Theramore. And before you say Theramore wasn't a threat, Jaina sent troops to the Barrens Campaign in Cataclysm and her troops attacked Horde troops. Theramore was an enemy base on Garrosh's front doorstep and he sought to wipe it out. They were against the invasion of the city, so there was NO way he was going to share his plan to bomb the city. Garrosh's initial plan to take the city by force was largely disagrees upon because they were apart of Thrall's Horde- one of peace. Garrosh's Horde wasn't about to let an enemy city supply troops to his lands to kill his people. So obviously he didn't mention the Mana bomb- it was his ace in the hole if his invasion failed (which it did).

As for Eitrigg: we don't know who attacked him. Garrosh never once showed him aggression, even when he did disagree with him. But who else could have hurt him? Malkorok. The Kor'Kron. Eitrigg is a Blackrock Orx and I guarantee you Malkorok and all of his Blackrock cronies pardoned by Garrosh would've hated Eitrigg because he sided with The Horde over Blackhands Dark Horde after Rend took over.

So it's quite likely Garrosh dismissed Eitrigg and the Kor'kron beat the shit out of him. Once he spoke out against Garrosh's plans to bring the Heart to Org, he was likely in no mood to tolerate Eitriggs council (a mistake, yes) and likely dismissed him, which was his final mistake. Just like Baine and Vol'jin, Eitrigg wasn't violent and Garrosh's plans for conquest were too much for him. At this point, Garrosh was having none of it. Anyone opposed him and his vision for the Horde was cast aside.

Eitrigg is the only one who councils Garrosh well (the Magatha incident was one of the few examples we saw). Yeah Garrosh should've listened to him more, I'll give you that. He's the only one who doesn't give up and betray Garrosh, or oppose him violently. He upholds his Oath until the end where's he's cast aside. Kind of depressing, now that I think about it.