He can dissolve the force via ritual, Nihilus has no need for such things.
Emotionless or not he still shows fear and frustration fighting Revan, something he did not fighting the Jedi Knight besides i thought you were with me regarding the Emperor being killed by the JK was just a Voice.
The Emperor would disagree with you, he thought Revan was the only one that could beat him. And the Exile had a chance to kill the Emperor with her lightsaber during this fight, she just used it to save Revan instead. That would make it Revan and Meetra<Vitiate, and Revan is stronger than Meetra so in reality it would only take 1 Revan and 1 Meetra or 2 Revan's not 100 to beat him.
on such a little scale like Nihilus he most probably can do it with his eyelash
yes, I agree that this was Voice, but lore says that he is emotionless
he would beat them anyway, Lord Emperor's strength is beyond his fight description with Revan