Doctor Kirin and Agent Essor are two NPCs who give Heroic missions and seem to be missing from the game, making it so that their missions can only be acquired by interacting with terminals either on the Republic fleet or ones on Corellia and Alderaan. Agent Essor (https://swtor.jedipedia.net/en/npc/agent-essor) should give the mission "Into the Killik Warrens" (https://torcommunity.com/database/mission/JtMWdDA/0) and I believe she should be standing around somewhere in Wardpost Luurdes in Alderaan. Doctor Kirin (https://swtor.jedipedia.net/en/npc/doctor-kirin) should give the mission "Biological Warfare" (https://torcommunity.com/database/mission/OZDbhR8/heroic+2++biological+warfare/) and although I'm not certain, I believe he should be standing around somewhere in the Republic Base or the Worker Tenements in Labor Valley, Corellia. In the case that they are still around but just difficult to find, I'd love for someone to tell me where, otherwise I'd ask for them to be re-added to their respective locations, thank you.