These individuals were members of the Turkana IV Alliance.
In 2367 they guarded the crash-landed escape pod of the Federation freighter Arcos and held the two pilots prisoners. They got into a shootout with Ishara Yar and an away team of the USS Enterprise-D. (TNG: "Legacy")
This man served as a lieutenant in the Turkana IV Coaltion in 2367. He led a group of Coalition members through a territory in the underground city followed by members of the Alliance. When he met the away team of the Enterprise-D he first pointed his gun on them but then led them to their leader Hayne. When the away team mentioned a deceased crewmember had been from Turkana IV, Hayne ordered his lieutenant to search the database for everything they knew about the Enterprise, a search that would lead them to their own colleague, Ishara Yar. (TNG: "Legacy")
These individuals were members of the Turkana IV Coalition. Following the encounter with an away team from the Enterprise-D in 2367, their leader Hayne offered assistance to the Federation in finding the pilots of the Arcos. He introcuded Ishara Yar, sister of the deceased Starfleet lieutenant Tasha Yar, but disguised his true plans, wiping out the Alliance by destroying their fusion reactor and enable a massive invasion of the Alliance territory. (TNG: "Legacy")
The guardians of Natasha and Ishara Yar were inhabitants of Turkana IV who looked after the orphaned Tasha and Ishara for "a few months" in 2342, after the death of the Yar parents, however the guardians themselves later disappeared. After this, Tasha took care of Ishara, until Ishara was old enough to join the Turkana IV Coalition. (TNG: "Legacy")
The parents of Natasha and Ishara Yar were inhabitants of Turkana IV who were killed in some crossfire in 2342, just after Ishara was born. According to Ishara, Tasha "hated the cadres" and "blamed them for our parents' death." (TNG: "Legacy")