Ori is the youngest brother to Dori and Nori. He was also the apprentice scribe to Balin. He went on the quest and later went with Balin and Oin to try and retake Moria. Which they were able to occupy it for a few years and then all three were killed in an attack on Moria.
Oin was one of the thirteen dwarves to go on Thorin’s quest. He was of Durin’s line. His brother was Gloin. He was also the cousin to Balin. From everything I’ve learned about the dwarves that went on the quest were all related to each other in some way. But that is something to discuss at a later date. 🙂
Look forward to reading your comments. 🙂