I think I have found the planet Atlantis landed on during the episode Lifeline. It is in the Pegasus galaxy, it has 5 moons but only 2 are visible from the surface (as far as I can tell), and it has life on it which in the show there is life on the mainland and of course it has oceans. Here it is!
Place "M35-117 (Atlantis)"
Body "RS 5303-2-7-481596-82 B4"
Pos (-9.670613655094547e-011, -1.981122116942284e-010, -6.542436897956621e-011)
Rot (-0.2765317402259822, 0.8396180347943373, -0.2173925080215675, 0.413898839998106)
Date "2019.10.29 22:51:42.20"