Hmm...if this is water-hand Aquaman, then they take the majority, since he can control water directly and his TP is vastly more powerful. Otherwise, it's, MAYBE an even split.
__________________ "One can do worse than be a swinger of birches..."
-Robert Frost
Well, if he's still got a mind, then he should still be susceptible. HOWEVER, the way Aquaman has shut characters minds down before has been physically, so it's possible that, if Bobby's mind wasn't physically whole, then he'd be immune. There is an equal chance that Arthur could just go about it another way, however.
__________________ "One can do worse than be a swinger of birches..."
-Robert Frost
Proof of what? In mist form he has never been mind raped, so I cannot use proof. That is why I said speculation.
However, if we want to delve into the situation let us take Dust and Xavier and superimpose them in the place of say Iceman and Aquaman.
When Dust goes all dusty, Xavier cannot communicate with her because her consciousness is scattered among her sand particles. In fact he can do nothing to her mind because it is so spread out that it does not have a central unit, yet she can somehow still stay in control.
Essentially Iceman does the same just via water. He stated the first time he did it that it hurt to be spread out so thin (thanks to Prosh) and it gave him a major headache. Yet after doing it two more times he was perfectly fine with it. He then stated to Jean (while freezing a celestial ship and everything it was composed of *molecules and stuff* ) that he felt like he was "everywhere" when she asked him where he was. He then formed himself a body standing right next to her.
Now if Xavier cannot deal with the mind of someone being spread out so thin, then what credentials can we give Aquaman to doing the same (unless he already has, but I would very much doubt that fact)