Missing Selkath
A Selkath in the mercenary enclave in Ahto West will spin you a disturbing tale of adolescent Selkath vanishing; apparently all of this began sometime soon after the Sith began arriving.
Talk to the Iridorian to learn about his role in this affair. He'll refer you to the Sith Embassy, who will understandably not be forthcoming with information. You'll need to find what info you can when you break into the Sith base during the main part of the quest.
Once you grab the datapad from the Dark Jedi Master, and (hopefully) free Sasha, return to Shaelas and break the news. You can accept his reward, or refuse it for a beneficial Light side bonus.
Republic Hiring Mercenaries
Another Selkath in the mercenary enclave will express a bit of worry over the fact that the Republic is paying exorbitant fees to hire elite mercenaries. The other mercenaries around the enclave will tell you little, except that the mercenaries that are hired have a bad habit of never being seen again.
Upon leaving the enclave, you'll run across a Republic officer recruiting a mercenary. If you ask him for a job, he'll refer you to Roland Wann, who resides at the Republic Embassy. Roland won't reveal why they've been hiring mercenaries until after you infiltrate the Sith base for him; once that's done, he'll fill you in on the details. Proceed on to the Hrakert Station to discover the fate of the mercenaries, then report back to Nilko for your reward.
Manaan Swoop Races
You'll run into Queedle in the Manaan swoop registration office. He's been trying to make his way as a swoop racer, but has had a hard time of it, due to the fact that his swoop bike just doesn't seem to be able to compete with the big boys. How you deal with him affects your Force alignment, in much the same manner as your dealings with Nico on Tatooine. Note that giving him money to improve his swoop bike actually gives you lower times to beat during the final tier, which merely goes to show that it is sometimes literally true that nice guys finish last.
Besides your interactions with Queedle, this quest relies on your cunning ability to steer a swoop bike. You'll need to beat the best times in three tiers before you finally achieve championship status on Manaan.