And didn't she say that there were people in the Stardrive section in Disaster? If so that would indicate that she could get a direction
Not really. If she only got a rough count
, she would know that the people in that section would not be silent = dead, or else the count would be only half as high. And if she got range
information, she would know that the stardrive section would be the only possible source at that range.
One last thing emotions are different from thoughts.
And mere presence might show up even when a half-Betazoid would have no idea about the emotional state of the presence, let alone the specific thoughts. A full Betazoid might have the same graduated response, only at greater range. (Even Deanna seems to be able to read thoughts, at extreme point blank range, and with a person she knows well - that is, Riker.)
Deanna did sense the Ferengi in the first episode they appeared.
Nope - in "The Last Outpost", she said she was sensing nothing from them. She speculated they had mental defenses of some sort. Which may well be true - but Quark in "The Search" indicates that even the best such technologies amount to very little, and a true telepathic shield would be priceless to the Ferengi.
In the second
episode, "The Battle", she sensed deception and danger from a Ferengi she had seen on the main viewer. Which may mean the Ferengi did not have their defenses up; that the Ferengi in question was much more agitated than the ones in the earlier episode; or that sensing was only possible at this closer range, without distractions, and/or with the reinforcing effects of the visual communications. Indeed, Betazoid sensing may be visually based to a great extent in every occasion... It's not as if Lwaxana Troi really did much telepathy with people she couldn't see face to face, either.